Have a good think and, if you really want some large blacks for breeding later on, I can put you in touch with some in Wales. If you get the chance, come to the Royal Welsh Spring Fair at Builth Wells this weekend and have a chat to some breeders. I'll be there and I can introduce you to some, if you like. My mobile number will be on my pen if I've wandered off.
On the question of registering two just because they'd be more saleable, don't bet on it. Pigs are moving very slowly at the moment, so you might well get stuck with them. Also, large blacks are one of our rarest breeds because people don't seem to find them that attractive (although I think they have a lot going for them). Lots of first-timers prefer the coloured breeds. The "large" in the name puts them off, as they think they might not be manageable, and the black skin can also be offputting to the uninitiated. Just a thought or two to ponder. Wouldn't want you to get stuck with something you can't sell.
All the best
Liz