I've tried it at least 20 times and my best attempt was 34%, then I had to reroll 8 times and fell too far behind. I think the feint legs would help a lot, but I don't have those. I could definitely kill it with good rolls, but the droughts just feel inevitable over an encounter this long.
Trying to get this skin reminded me why I hate Outlaw so much. The swings in RNG are just stupid, and if you roll poorly for the umbral + shield combos, you just die.