RE: OS10 FSR
Just rebuilt mine by stripping it down and cleaning every bit of crud off it inside and out making sure all the oil groves and holes were clean.
Fuel was 15% nitro 15% cooolpower 70% methanol (YS DZ170cdi brew) with an extra 10% castor added to the brew. I'll make up some proper fuel later when I get some more methanol.
Prop 7x4 APC, very old OS #8 plug, best static rpm 15,850....
PS. Control line version bought at a flea market in the late 80's that did years of service pulling up my 2.5M glider when I was a kid.