Because competition is never stopped for very windy conditions, weighting and tuning boomerangs has become an art. In addition, as throwers have become more sophisticated they have developed innovative tuning techniques to adjust and fine tune the flights of their boomerangs.
Proper weighting can be used to gain more control in a strong wind, get more distance from your boomerang, increase the hover, shorten the hover or adjust the trajectory of return. Some people like to weight every one of their boomerangs in the same spot to accommodate their own throw. And others like to have identical boomerangs weighted in different ways to accommodate different tournament events and wind conditions.
Experimentation is the only way to learn the art of weighting and tuning. Every different boomerang style has its own specific flight characteristics due to its aerodynamics, wood density, and weight balancing built into the 'rang. And like our fingerprints, each tree in a stand can be different (ie. less or more dense) than the tree growing right next to it.
There are too many variables of design for weighting rules to be iron-clad so don't be afraid to experiment. Sometimes combined ideas produce the desired effect.
Weighting can be used to adjust the flight of a particular boomerang to your particular throwing style. Once you are getting consistently accurate returns - begin moving a weight, or weights, around the boomerang to see what the results are. Some people like to weight every rang they own on the lift arm near the elbow.
Things used for weighting are coins, lead tape or flattened lead pieces of different size. They can be attached with electricians tape or colored plastic tape available at hardware stores in the hobby section. Attaching the weights to the bottom of the wing decreases the lift which is desirable in a strong wind. But weights attached to the top of the wing work very well, too. Experiment to find out which method produces the desired results.
I used to always tape the weight in such a way that the tape was smoothly attached to the boomerang surface with the weight not protruding beyond the tapes edge. This produced an aerodynamically smooth surface. But, creating drag works extremely well in fighting a strong wind and is not necessarily a bad thing even in light wind. Creating drag can be accomplished by numerous methods, drilling holes in the wing or using anything that stands up a bit off the wing. It could be an abrupt transition from wing to coin or even a small piece of weather stripping. Or even a folded piece of tape that forms a spoiler (or wind flap) on top of the wing. It can stand up from 1/8" to 3/8". In other words, anything that creates drag.
If you have taken the time to study aerodynamics you know that flight is achieved through a delicate balance of controlling lift and drag. Drag is also an excellent way to slow the spin down during return, which reduces hover time and makes it easier to catch. Drag is desirable even in calm winds.
For boomerangs with holes drilled in the wings, I like to tape over the holes on the bottom of the boomerang with small pieces of tape. As the wind increases remove one piece of tape at a time to fully expose a hole. If you need more drag, expose another hole, etc. Different flights can be achieved by exposing different combinations of holes. When the wind is blowing hard and all the holes are fully exposed and you need more drag, try a tape spoiler on top or a trailer of tape off the back of one wing. A great technique when you have two holes drilled near each other is to use garbage bag ties. Loop a tie through the holes and let it stick straight up or down. If you need more distance and the wind is blowing hard don't be afraid to tape 2 nickels or 2 quarters near the lift arm tip. One on top and one on the bottom.
Three winged boomerangs can be weighted in numerous places. At one or all of the tips, in the very center or along one or all of the wings. A good trick with a tri-blader to keep the flight low, is to have a trailer of tape flapping in the breeze behind one wing. This is very effective in a wind. The tape should stick out about 1/2 inch behind the wing. Remember, weights near the tip of a boomerang increase the distance.
Adjusting the trajectory of return is usually for short distance 'rangs, such as a Fast Catch competition boomerang. By moving the weight(s) around the boomerang, usually near the elbow, you can adjust where the 'rang is returning. Some turn so tight that no matter how you adjust to the wind, it's always coming around in front of you, or they may come in behind you every time. So move the weight around to get it to come in where you are comfortable with the catch. (Careful flex-tuning down is sometimes necessary to keep the flight low, especially with an aggressive Fast Catch boomerang.)
Check your boomerangs periodically to maintain flatness. Refer to the Warping section in the instruction booklet for general flex-tuning tips. You want most boomerangs to be perfectly flat, or slightly clicking tips when tested on a FLAT surface. For some longer distance 'rangs, try a special warp. Basically flat, but with an up TWIST on the lead arm and a down TWIST on the trailing arm. The up twist is called a positive angle of attack and the down twist is called a negative angle of attack. That will result in a more elliptical flight path. For a flat round flight, try a gentle down warp of either tip. With some boomerangs, flex-tuning the lead tip down and an up TWIST on the trailing arm can produce a low flight.
If any boomerang is climbing too high, you may be throwing with too much lay-over (sidearm) or you may have an up-warp on one or both wings. Carefully flex-tune to flat, or possibly down warp one tip.
If a particular boomerang is just not flying the way you think it should, check it very carefully for a subtle warp. A slight warp that you can't see at a quick glance can dramatically effect the flight. Larger rounded elbow boomerangs like the Delicate Arch, Kilimanjaro, Adirondack, etc. can develop a subtle warp that dramatically effects the flight. Check them often.
I prefer throwing every boomerang (except the Kilimanjaro and Mirage) from the dingle arm. The dingle arm makes a better handle and the balance feels better. It also has more distance that way and fights a wind better. A dead vertical release gives you a flatter flight and a release with a bit of layover gives you a climbing flight. I throw almost all boomerangs with a slight degree of layover. In a dead calm throw with a more laid over release and as the wind increases stand the boomerang up to a more vertical position and closer to 90 degrees "off" the wind.