Just a tip,

If you need weights, lot's of them, get a bag of playsand, a box of sandwich bags, some tape, (cheap, dollarstore masking tape works for this, but not much else!) a gallon of water, and finally, some bleach.
Mix in about a tablespoon of bleach (exact amount not crucial) in the water. Mix the water in the sand until its damp, not soaking wet. Fill baggies about 3/4 full, and close with tape.
These make great CHEAP weights for anything, and they conform to the surface. They don't slide around like batteries, or steel blocks. They don't damage the surface either.
The bleach is just to keep bacteria/mold from growing in the bags.
You can make 40lbs. of these for about 5.00 bucks.


Jetts

I use paperback thick text books, phone books, and catalogs. They also conform to wing curvatures and with a lot of area.

lead shot from the local gun store is my method (put into sealed ziploc bags).

- George

And then I put the baggy filled with shot into an old sock to keep from scratchin up the finish, and keep a long thin shape.