I'm aware Modtweaker currently adds support, but @joshiejack has stopped working on it a while ago. I don't know his policies on giving you the code to integrate it with Mekanism, but I saw Blood Magic now has the classes from ModTweaker, and they're credited to Josh. Here's the classes you'd need to implement in order to get it working.

I'd rather not integrate with any other APIs right now, as I stated in an earlier issue, Mekanism's integration is already a mess.

That's fair. It also helps that sometime after I requested mods about MineTweaker support, Jaredlll08 took up the task of continuing modtweaker, over at the new repo.