Button can be fixed, but it will need to be disassembled to do so.
My istick 20s vary in weight between 89, and 90.43 grams, only have one 30 so far but it weighs 93.45 grams. Pretty close to the same weight, in hand I can't really notice the difference.
I have a 1500 mah general spinner battery that i used to keep with me as a secondary battery in my pocket with my istick 20w. I was concerned that having 2 isticks would weigh my pocket down considerably.
I actually went to the post office to use the digital scale on their postage machine. The istick weight like 4.6 ounces, and my ego battery weighed 4.2. I might be wrong about the number, but I know the difference was only 0.4 ounces. Still a bit pocket heavy, but that's only because I'm using Kayfuns on both of them now.