All that said, the only almost-adult buck we have at the moment is the rex doe's brother, who has more well-furred feet but has pinched hips and is very small (He's still not at his adult size, but his sister is 11 months old and she's 2.5kg/5.5lbs, while my cali is 4.2kg/9.2lbs. All "Standard" rexes here are this size).
Attached are pictures of the trio, to illustrate what I'm working with (The tricolor tuxedo pattern is called Jaguar here and seems quite sought after)
So, with what you just said, I would breed the rex to your Fauve girl AND the rex does, get some half rex big rabbits from the fauve, then sell most of the pure rexes,
Your Rexes are very pretty - I also like the tuxedo "jaguar," although it would not be considered show quality here - and they have beautiful color and separation of spots. But... I'd be
very hesitant to use nothing but tris in a program designed to produce bunnies for sale. Tricolors are broken harlequins, and breeding brokens together can result in some serious health problems in the kits. Statistically about 25% of the kits will be "charlies," kits that have two copies of the broken gene and relatively little color.
Many breeders, myself included, only breed broken x solid, to prevent this possibility. Charlies are cute, but they commonly have a tendency to develop megacolon. That is a sad disease, frequently connected to having two copies of the broken allele <
EnEn>, that can show up anywhere from a few months to several years of age. The point of avoiding breedings that will result in charlies is that not only do I not wish to breed unhealthy rabbits, but I especially do not want to sell someone an apparently healthy rabbit that can become very sick after a time. It is usually fairly easy to spot charlies, and should be especially so in a line of Rex that seem to run to the heavily-marked end of the spectrum. (Charlies are pretty much the opposite end of the spectrum, if you're hoping to produce more jaguars.)
However, the first rabbit pictured (darling!), given what you say about all the rexes around being tricolors, would make me wonder. Its dam is apparently a broken; do you know whether its sire was, too? If so, I'd watch that rabbit closely for gut/elimination issues, things like irregularly-sized poops, intermittent appetite loss, etc. If it is a charlie, and you breed it,
all of its kits will be brokens; this will be true whether you breed it with a solid or another broken. That's the nice thing about a
healthy charlie - you only need the one to produce all broken-colored kits (if that's what you want).
Sometimes identifying charlies can be a bit confusing; a genetic charlie can be fairly well-marked, while you can mistake a normal broken for a charlie, because some brokens are just lightly marked without being genetic charlies. The young Satin buck pictured below looks like, but was NOT a genetic charlie; he was faulted on the show table for being one (at the time, the ARBA Satin breed standard did not have a DQ for the charlie pattern). He became a Grand Champion, he sired many other Grand Champions, and lived a healthy life till at least the age of eight (not sure just how much longer he lived, since I eventually sold him).
I think that this is yet another reason to do some crossbreeding with your Rex (especially if you can't find a solid colored Rex - one of either sex would do). If you breed your tri Rex buck with your Fauve doe, you should get some harlequin and/or tri babies out of that, which, although they probably won't have rex coats, should be attractive to buyers that like those patterns (and will all carry the allele for rex).
If it was me and I did breed the tris together, I'd be prepared to cull any kit with less than 10-20% color on its body, especially any kit with a reduced or no spine marking. I would grow them to butcher weight for my own use (although, if they have early megacolon issues, they won't grow well anyway), but I would not let them go beyond that, and I certainly wouldn't plan on being able to sell them.
So, either way you go, you may not have too many marketable bunnies in the first round of breeding. You'll probably either get all normal coats (in the crossbred kits) or some rex-coated charlies (in the purebreds). To be sure, in the tri x tri litter(s) you'll most likely get some solid or broken Rex that you can ethically sell, and you could keep the best solid kit(s) for breeding. But if you breed the crossbreeds with each other, or back to the Rex, you should start seeing rex coats coming out in roughly 50% of the kits in the F3 generation.
