As a general rule .325 will work best on 50cc or less saws. 3/8 LO-Pro on limbers 42cc and smaller and use 3/8 on the bigger stuff 55cc and bigger. Type of wood matters too, but the is a good rule of thumb.
+1
Exactly the same thing I've found out here. Bar length makes a difference as well. I don't like the 3/8"LP past about 14", and the .325 past 18".....Cliff
+1
Exactly the same thing I've found out here. Bar length makes a difference as well. I don't like the 3/8"LP past about 14", and the .325 past 18".....Cliff