the base stats, first 2 stats, usually strength and vitality for tanks, are always going to be capped on crafted gear. the other stats are close to capped, and then you can add all other materia to cap. also certain levels of materia cannot be put on lower ilvl gear. IV materia cannot be put on raptorskin merchants purse which is i47. only IIIs can. i think it is 1-30 for I. 30-40(45) for II and 40(45)-55 for III 55+ for IVs