I am 5’8", 150lbs and have been surfing for a few months. I have the 7’6" nsp. How would the 6’10" compare to this? Would a 6’10" board be big jump at this point or is it a reasonable transition?
Depends how the 6’10"er is shaped.
If it’s another funboard, you’d have an easy transition, with a little quicker turns and easier handling.
If it’s a big guy tri, a little more adaptation time, but still relatively easy and much quicker and easier than NSP.
If it’s a full on mini gun, maybe you aren’t quick enough or stable enough for it, so will be a somewhat difficult transition, maybe easier if you just got a 6’3" small wave board or a 5’8" fish.