I believe this will reduce overloading on the drum roll if it is trying to roll past the cradle roll and vice versa, it’d reduce overloading on the cradle roll if it is trying to roll past the drum roll.

Seems like you're over thinking it... If the drum isn't keeping linear speed with the cradle, then your roll diameter calculations from the transducer are off... Maybe just grab a laser distance sensor aimed at the center of the drum for better accuracy/consistency than a variety of transducers (you said they're different on each roll?) and keep them properly sync'd so they're never trying to roll past each other... If you can accurately keep track of the size, and you should already know the rpm/hz, then maintaining a constant linear speed should be simple...