Good morning
I used SAITO FA-50 from '92 to '96
Propeller: 13x6 Merati made in Italy with thinned blades
Venturi: self built 6.9 mm diameter with Supertigre spraibar (4 mm.)
Fuel: 70% methanol-20% oil (All synthetic) -10% nitro
Plug: OS "F"
RPM 8000-8200
With this setup, the engine pulled a heavy 1900g (67 oz.) Model without any problems.
I am currently reading on this forum that many people use 20% of nitro, if I still use the 4T I would undoubtedly try this option.
I hope that this helps, Massimo