I may be quite wrong on this, but I think you should try many attempts instead of a single big one.

Based on Chibikika's experience spending lots of Pero puddings at the same time, it was needed a lot of luck to get the limmed SR.
From what has been posted at the moment, there's a chance for really poor rewards in exchange of a big donation, but I don't know the limmed SR success rate for donations as big as 8 card reveals.

I'd like to wait and read more opinions, I'm in a very similar situation like you are, having extra card reveals and looking forward to get that damn limmed SR