Two rear axle standards in this house!

I have a QR bike that lives on the trainer, girlfriend just picked-up a Crockett with a 12mm rear (selling-off her old Evo). So, what does everyone recommend when it comes to two rear axle standards in this house?

She and I have a damn-near identical inseam but she needs a 172.5mm crank and I ride a 170, different saddle set-backs, different saddles, so we can’t ride the same bike.

So I’m thinking there is no more reasonable choice than to buy another smart trainer. We already have a 1st gen hammer, not sure which is next but probably a Kickr Core to travel with. Any other ideas?

Why not just change out the cups each time? Wheel on trainer? Swap out the seat and post per rider? 172.5 to 170 is neglegeble for training as long as you account for it in saddle position. Swapping from 170 road to 175 mtb is easy enough to adapt to that I don’t even notice it anymore.

Or, if you don’t care about the cost, but another trainer.