Start at the last MSQ ilvl req then go up by 5-10 every dungeon... should at least stop particularly bad offenses. At least by the last dungeon of SHB someone should be AT LEAST i385-i410. Since the last MSQ Req is i360 for Ghimlyt, tho I'd argue the last solo-instance kindof prefers i370+

Which assuming the gear flow in SHB remains similar to HW and SB, i400 should be matched/surpassed by lvl 75.