Ouch at those junk materia prices! Sorry, I can't speak for economies other than the one I work with. Still, I plugged your 1k value into my formulas and it told me that, if my other numbers are right, triple melded cashmere hats of casting are still the best for you. It will cost you an estimated 60k per success, for 120k per level, for 600k to get from 85 to 90. All estimated and theoretical, of course.