Well i really got no luck with ruins. No culture ruin in last 6 tries. I try to find a way to have nice starts with less luck factor. Germany UA is highly related to luck. Unfortunately, i couldnt push an enough good start(after 4-5 civs killed) to finish strong enough. I need 75% rate of barbs recruitment to keep enough units in the field for each side.
I take a lot of risk. I can lose units when RNG says that i will survive with 2 hp...keeping promos to the limit to keep the most insta-heals possible. Remind me my super level 3 spearman with 3 accumulated insta-heal lol
In last games i begin to play with Wu Zetian.
Since you have more time than I do, try Japan. Nothing special on the UU for this gauntlet, but the UA should allow you to do more with less. 4 warriors or 2 swords can take done an undefended/unwalled capitol without losses.
I've been playing around with Japan in a 1 city (until IW) and it seems to work ok.
1) Reroll until you have a starting location with a mineable luxury and at least 2 (preferably 3) good unimproved tiles (3F/0H, 2F/1H, 1F/2H in a reasonable combination).
2) Settle the luxury. Trade it when you have a chance to an immediate neighbor (immediate neighbors will be knocked off late, so there should be no exploit issues).
3) Go straight for IW. You should get this in the early 60s if you are at a spot where you can get some pop growth.
4) Build nothing but warriors. Steal a worker for the capitol. Yes, this comes late.
5) Go for the free settler. You need 1 culture ruin to make this fast. You don't need a culture ruin for turn 68 or so (too slow to win this, but ok otherwise). Free settler settles iron.
6) Get an army of 4 warriors in place to knock off a distant civ on turn 50 or so.
7) Get an army of 2-4 warriors in the other direction under open borders for the swords upgrade.
8) Keep 2 warriors around for a swords upgrade to knock off immediate neighbors.
Admittedly, I haven't pulled off sub-100 yet, even in a test game, so I don't know if this can challenge 91. I've come very close to 100. Biggest randomness is availability of iron. But even with lower attack values, Japan's UA removes a lot of randomness from attacking. Who you can sign open borders with is also random. It's critical to move things into their proper places by the time you hit IW. It's also critical to sign any open borders agreements before you knock off that first civ with the warrior army.