Foamcut thanks. I'm getting back way more than I'm giving, but it's nice to be appreciated.
One thing I've noticed is that all the large OS engines from the 120 to the BGX 3500 come with the OS #8 glow plug, which is their cold plug. The manuals for the engines recommend 5-10% nitro. Usually the conventional wisdom is to use a cold plug with high nitro applications (over 25% nitro) so I think I'm missing something about glow plugs in large glow engines. But I'm pretty sure I need a hot plug in my E85/glow application. I ran out of oil for mixing up fuel, so it may be next week before I can continue my experiments. By then I should have my new tach as well and quantify the total power output. I suspect the power output will be very close to glow power. I'll be able to compare spark ignition on the same engine so I'll have three power output readings for the exact same engine, the ASP 108. I'll probably mix up gas/oil for a trial on spark as well, making it four output readings for one engine. Ought to be interesting.