I only know the things I've heard from others, and am not a breeder so have no firsthand experience or data of my own to compare these claims against, but I'll air what I've heard. This may be stuff you already know.

-Apparently female caramels have smaller clutches on average than other females; like I said I have no data or names to support or debunk this but I have heard claims from several breeders over the years that their caramel females lay consistently smaller clutches than their other females who were cared for in the same way and same conditions. Apparently the sub-fertility is not an issue with hets.

-Caramels DO have issues with kinking, that is certain, nobody has figured out what causes this and to my knowledge lowering incubation temperatures has not yielded any solid results. However, I have heard claims that breeding a visual to a het or a het to a het decreases the odds of kinking in visual babies; again I have not seen any data or breeding trials to back this claim up.

To my understanding, a lot of people dropped the caramel project for the toffee/candy project and the ultramel project because of the similar color palette and lack of gene-related issues. Maybe, if the possibility kinking scares you, one of those projects may be a better fit. It would be more cost effective to go caramel though, lower price tag generally as some people avoid it.