I want to also point out band sizes as well,
I am using #69 rubber bands, #64 are way too short for the 17" chord of my wing.
I have yet to find a proper size band at any office supply. Yes I can put two 64s end to end but I consider the joint to be more of a weakness than a used rubber band of appropriate length that is still in good shape.
I have yet to have a used rubber band break. I have had some brand new ones break (I had a new one break a couple of days ago and smack me right in the face, everyone got a good chuckle out of it)(I think I got an old box, I told my LHS about the bad ones and got a free box)
I use 10, 4 on each side first and the last 2 crossed to lock them in.