Someone might have already have said this,but to me ,It does'nt make a difference in ring thickness,up to a point. What matters is the thickness of the early wood. I have built good performers from wood that has 2 growth rings in the finished limbs,and also good ones with 6-8 rings in a 1/2" finished limb.It does seem I can get by with a little thicker early wood layer with the thicker late wood ring. JMHO God Bless