I don't have any measures to go by, but I did talk to Bob.
Arthritis in the back, shoulders, etc, has me dropping weight... so in conversation, Bob suggested getting carbon/foam core for my bow and assured me that the C/F is much quicker and I'd get 50# speeds w/ bamboo core from a 45# set of C/F core.
Came to pass that someone put up a set of Cheyenne L/B limbs, at 45# and I lucked into them!
All I have is my perception, but after shooting 48# boo core recurve limbs and then going to same "D" config L/B limbs in foam core/carbon at 45#, I've been impressed that a) the l/b or F/C are much quieter. They're smooth, but "feel" different in the draw... more "authority(?)" when pulling them... something but can't quite put words to it.
Performance is great and I'm tickled!