I think you're making a good choice by choosing to avoid pairings that have a higher than usual chance of physical deformity. Yes, deformity can occur in any clutch, but when it occurs, for example in a normal clutch, you can think to yourself 'it's just one of those things'. If it was in a super cinny hatchling (for example), you'd be thinking in the back of your mind 'I caused this'. I think that would be the big difference from me, from an emotional standpoint - it's much easier to accept something when you feel as though there was nothing you could do to prevent it.

And besides, it all comes down to risk in the end and what level of risk you personally are willing to accept; the risk in a normal clutch is much lower, and that risk may be acceptable to OP, whereas the risk from a cinny x cinny pairing clearly isn't.

From an ethical perspective, I think it's wrong to do any pairing where the offspring have a significantly higher than normal chance of a health complaint, be it physical deformity, a neurological issue, or whatever else, so I think OP is doing the right thing