1. No Fracture, the best rotation now is H IDC P TTT H TTT P IDC H TTT P TTT Repeat.
2. Onion Armor by a mile. You pretty much always want the higher iLvl item, regardless of secondary stats, because the higher iLvl should almost always have higher main stat, in this case, STR. The only reason you'd take Darksteel would be if it were HQ AND you got more STR than onion through materia. Not sure if that's possible, I'm melding dumb.