General

% magic issues/Ideal weapon potential for mages?

2 of the lines on my wand are % magic. But rumor has it that the % magic potential doesn't really work anymore.
Ever since BB, I've been trying to find a way to test this myself (either finding a weapon with similar m.atk to mine, which is hard, or finding a pair of similar weapons, one that has % magic & one that doesn't) but so far haven't had any luck.
People don't seem to have concrete answers, either. But I may as well ask again:

1) Is this true & proven that % magic doesn't work?
2) If so, what should I cube my wand for? (% int? total damage? 30% boss?)
3) Are any of those other potentials glitched? Word had it 30% boss was also broken.