[MichelB]

(I didn't have time to read the entire thread so I apologize in advance if this has been said before but...) SWISS CHEESE!!! While my team always tries to estimate weight and remain under the limit we always seem to go over, that's when we break out the hole saws and cut as much extra material as possible away without compromising the structural integrity of the part. Since most of the force is taken on the edges of the piece, cutting holes in its center won't affect it too much.