Here’s a caul I made using a 2x12x12. I cut it in half length wise, and then cut the arched piece out of one of the 6’ pieces and screwed it to the other 2x12x6’ piece. I took the left over from the arched cut land screwed it to the back side for a straight caul. I can heat and clamp sideways and up and down at the same time, so can usually work on straightening, reflex, and propeller twist all at the same time.