As for armors, Max strength at Tier III is 15, on Tier IV (lvl 5) its 20, Tier V 25, and so on.
Id say in the 5-20 anything around Max str-5 is good enought.
At MQ, preferably 45+, but i use for example 42, and works okay.
As for having every 5th level, its very nice, but only if u wanna spend alot of fg. I would rather do every 10th lvl, (5/15/25/35/45/55)
and spend the fg u save from buying extra tiers on improving the ones u buy.
Same applies for charms, and ideal is ofc to have perf charm on every lvl, but its way too expensive for 99.9% of users here

My 2 cents on it. Hope it helped you, and dont hesitate to PM if u wonder more
