Currently all recipes are hardcoded, It will be great to have CT support in order to customize machine recipes. This feature will be essential for it to be used in modpacks.

Unlikely to happen as I have no interest in adding support for craft tweaker on any of my mods. If someone else wants to make an addon to implement it that would be fine. Otherwise we already have plans to implement our own system for this using JSON like we did in 1.7.10. As well MC itself will provide paths for recipe server side datapacks in the future.

Anything that support customization is fine