Again not saying you can’t – people have done it and had no issues, but if I had a UL deck and an non UL deck gathering dust in my garage I’d be chopping the non UL deck.
p.s. re Carbon Array – if you cut it yes you lose it but it’ll be no worse than a deck without carbon array – stick with decks with what we call HYBRID GLASS in my opinion – these have a composite layup of at least one layer of TRIAX glass – so after cutting your going to get some torsional benefit in the new splt vs a stock BIAX deck that’s split – so IMO I’d be more focused on splitting a HYBRID GLASS board ( = has TRIAX GLASS) and less worried about Carbon Array being a plus or minus – the CA is a non event once you split it… you may get some incremental benefit back once your foots bolted back down in SB mode to the Carbon Array but I’d assume you’re getting a split board not a torsionally responsive carbon array deck out of the mix once you cut – but sticking with a board with some TRIAX glass would seem like a good call… all that said its clearly going to be a different deck once you chop it so assume some inherent re-learn curve is going to be a must once you bolt it back together and ride it as a SB.
p.p.s. Again I wouldn’t split a UL board but that’s just me – none of our, or anyone’s non split boards really are designed for this kind of post manufacturing modification – so clearly it could all go wrong fast in garage or on snow so I can’t endorse it, but which ever board you choose…. good luck!