I think you can challenge them as many time as you want the first time (the one where you can win, I don't count forced loss
). For second time (where you're betting your light weapon), I don't know.
I used the bronze halberd IIRC and I don't remember which level I was. I was playing warden with the bleed and poison attack from the corruption tree. I was relying mostly on the DoT for damage and guardian + warden's defense stats + aura of healing to not die.
If you're relying on your weapon, I think that fire is the best element to get (which type of weapon depend on your skill) but check with the reaper, he can give you tips on the domina you're fighting.
Poison and bleed are really strong tho and I'd recommend using it if you can.
I tend to over-farm in those types of games and I took a good amount of time that there was 5 forced loss for mary before getting the cloak (I was faster to understand that it was 5 more forced loss once you have the cloak
) so I over-farmed even more in that realm so I might have been a bit over leveled (5 forced loss in a row is too many imho, one or two top would have been enough).
I don't think maki and mika are hard to beat (at least with warden).