Depends on how, and how much, you intend to taper them. A barrel taper won't lose any spine. If you take a 23/64 shaft and taper the back third down to 11/32 it won't lose much, if any, spine. If you take that 23/64 shaft and taper the back 2/3rds down to 5/16, you might lose several pounds of spine. It's really something you'll need to play with to find out how much you lose with the amount of taper you want.