I have 3 older Stihl chainsaws 201T,009L,041AV. The 041 smokes a lot. Just bought all 3 a month ago. I have been watching You-tube videos on 2 stroke oil…called CERMA. Anyone out there recommend this oil to use ? If not , What about AMSOIL or Royal Purple ? Any of them snake oil ? Over the years I've bought the cheap stuff and don't want to do that with these Stihls. I appreciate any of the help anyone can give me.