Yep, not off the top of my head. I've done 1 hour Rodinal stand (With pre-wash) with C-41, so that may be a starting point, though I think I remember that being a bit under for E-6 films.. I cant remember.

But it can work well to produce nice negs.

Also if it's so expired that through E-6 it's basically clear.. using an alt B&W developer as an E-6 first developer works very well for that too.