necroing my own thread. went the multi-card route in the end, three cards, no kyc anywhere. nullroute was right about the shape of it even if he was insufferable about it.
what i got wrong in the opening post: i asked which single card handles 40k. the question has no answer. the actual question is how much operational annoyance a month you'll accept to avoid a filing, and that's a number only you have.
not marking this solved because it isn't.