Dave, what Bear model had the hand shock? I've had several and never noticed hand shock. Some of the shorter ones, like the Kodiak Magnums, had considerable finger pinch, but that was not unexpected with a short bow.
I have never shot a Shakespeare. I've looked at several, but the grip never fit me on them. I would hesitate to jump 15# in one fell swoop. Ten is doable though, so if you get both you could transition from the 45# to 55# a bit more easily.
I went from a 45# Grizzly to a 50# Herter's to a 55# Mahaska. The 5# jumps were a piece of cake. Now I move back and forth from 46# to 55# with no issues, but I do shoot all of them fairly regularly. Lately the Kanati and Shelton have been getting the most attention though.
Let us know how you come out on the deal. If they are straight and in decent shape, $200 for the pair is not outrageous. If you can do the deal for around $150-175, you shouldn't ever lose any money should you decide to sell one or both.