The manual (on stone tablets) recommends 24:1. There are no gouges or scratches on the piston or cylinder and I have no carbon build up on the piston top.
Today I use Stihl 2 cycle oil mixed 50:1 in a Pioneer that I purchased new in 1980. Use a quality 2 cycle oil and mix it to the OIL supplier's recommended ratio.› ♥ ♥ Mcculloch Mac 3200 Chainsaw Owners Manual ♥ ♥