I'll clear after the RG but generally only if it's a particularly good map like the A5 graveyard or A1 jail. Otherwise I've got more than enough keys/fragments/etc that I'd just as soon start a new one and get another RG (not an amazing legendary drop rate, but still pretty good) and more blood shards.
When solo I've just been starting GRifts at 1 and then jumping to like 10-11, 18-21, 25-27, 30-32 and clearing them and then upgrading gems. I can do them in my MF gear (170%, not amazing but hey it's almost an extra 6th legendary after every 5... technically at least lol) and GR RGs have very good drop rates and most of those difficulties can be cleared in 3-5m. I think it's a pretty good legendary per hour return and I've got tons of trial keystones to burn and it at least gets gems to 25 without much problem.