If Ceredigion votes Conservative, never mind eating my hat, I'll eat the cuddly toy dragon I currently have as my avatar!
Considering it is now a 4 way marginal it's quite possible that they could win it on a very low vote share, especially if the boundary review goes through and it is linked with parts of Pembrokeshire.
I think the general consensus (here at least) regarding the boundary review is that it's not going to go through, and either way it's not a certainty that's for sure. I also suspect that the Conservatives are probably close to their ceiling in Ceredigion, and that in the immediate term the electoral narrative will likely paint the seat more as a Plaid Cymru/Lib Dem contest, with Labour in with a chance under landslide conditions.
Put simply, I'd take that bet and not lose a second of sleep over it.
Addendum: If one fancies continuing this conversation, I'd do so in the Ceredigion thread, personally.