Definitely a two deck setup. A single color only would be a nonstarter. Most home games use a two deck set up that's in play at the same time.
Piatnik's high MOQ is why group buys started by small groups here have failed in the past. Do you have any retail partners that you can offload some stock onto? Depending on price, I think you'll be able to guarantee about half of that amount in pre-orders, but the rest is where it gets tricky.
If you're dealing with Modiano, I'd be up front and honest with them. Tell them they fucked
@desjgn over and that a large chunk of your buyer base is very hesitant to do business with them. Any business with them should come with a 100% satisfaction guarantee, in which any errors found in the printing process that make the cards marked in any way would require a reprint fixing the mistake on their dime, or else no deal.