My 2 stroke experiences started with outboard motors from the 50's & old motorcycles from the 60's. I ran 40:1 in every 2 stroke motor I ever had & never had fouling problems.....But, they were always oversquare motors (bore larger than the stroke).
With the Simplex, you've got a combination of undersquare design (stroke longer than bore) as well as barely adequate cooling fins. This makes me cringe about the idea of a 50:1 ratio. I do like to hear that you guys have been able to get away with the leaner mixes though. I'd rather fuss with a fouled plug once in a while vs a siezed piston.
I think I'll go to 32:1 to see how much smoke it generates.
Mike Sal