Looks like this question has many options and it mostly goes by personal preferece.

I have just started tying them down to smaller sizes in recent months so you'll have to take my answer with a grain of salt. So far i have tried them with the soft under-fur from buck tail, kip/calf tail and craftfur. 1st choice would be craftfur - easiest to deal with for me at this size and the action is excellent. 2nd choice would be kip - it seems to hold a panfish profile pretty well but also seem to be much more slippery and harder (for me) to lock down the upper/wing section.