I ran my old LB (pre Dura-Force) engine with 32:1 LB oil for a couple of years - with many exhaust port clogging problems. I had to get a new engine plate because the tapped holes for the muffler from the bottom were stripped out from the on/off.
Last season, I started running 100:1 Amsoil. I've had no clogging problems since.
I also have four pieces of Stihl gear, trimmer, edger, hedge clipper and blower. I used Stihl oil, 50:1 until this past season. I switched to the same Amsoil 100:1 mix I used in the old LB. They had no clogging problems and started/ran better.
My Toro Sizuki still is running Stihl oil, 50:1. I've not had the guts to put 100:1 Amsoil in it yet -- it has ran so well for two years, with no clogging problems (used about 130 gallons of mixed fuel this past season). Maybe next year I'll skip the Stihl oil and go to all Amsoil.