Kairos - OK, Fai fuel got it. Even using castor at 50/50 with Klotz, I have never had a problem. Striaght Castor requires some engine maintance yearly, or at least I would do it yearly.

Afterrun oil - I like Marvel air tool oil, Can't get it here in Canada, I use a close relative called Kleen Flo and it seems to be the same stuff. I use a lot of afterrun oil, in the tablespoons. Lately I have been using 1/2 air tool with 1/2 ATF trans oil. Seems to be good also, a tad drier than straight air tool oil.

I don't think that the brand or type of oil is most important, using lots of oil is however of whatever you use. Whatever you do, do not get the afterrun in the tiny bottles for lots of $$$$. People tend to scrimp on the oil which does not help your engine. I use the foam ear plugs in the intake and muffler so when you hang your plane in the vertical the oil does not run out all over the floor.

Richard