In my opinion the easiest most forgiving build to play at the 90ish range would be a Shadow Impale DH. You have over a Billion toughness and you do a crazy amount of damage. I was able to do a GR 96 with no augments and only a couple ancient items. This builds ease of gearing also comes from the fact that you can upgrade daggers as a DH and you have a 50% chance to get a Karleis Point so getting a solid ancient weapon should not be to hard to farm. This build is so versatile you could do Split Bounties, T13, Gr Speeds, Gr Pushes up to 110 with great gear, anything. It transitions to group play so effortlessly and can function as a Rift Guardian Killer up to very high GRs for group.