I think it depends on how much power (and therefore recoil) you have with your bowling pin loads. The 681 and full lug barrel will rise less with heavier loads than a 3" model 10, but do you really need an excuse to buy another gun to test your hypothesis?
I agree 3" model 64s tend to be on sale more often. Most of the 3" bull barrel model 10s I've seen were -8s, and these spanned the change from pinned to unpinned barrels. Please let us know what you find.