After some consternation over how much combustion chamber volume I should put into the glow head I was making and making a pest of myself by being lazy, I went back to the beginning and started reading. Three hours later, (its 2 AM here) and only at page 15, I started to skip ahead. At page 39, I found much appreciated info from Ringwinger and others. Thanks guys, it was all there.

Then I come here to post my thanks and MORE good info. Thanks Will and AV8tor.

Pictured is the result. Using EFFECTIVE CR, I've done it up a shade overcompressed at 13:1. I was concerned over losing the benefits of squish band but it appears that it's not that important. So, I'm overcompressed to start but I won't start there. I've made up multiple shims of aluminum in various thicknesses and will use them to affect a much undercompressed condition. Based on all the good info on this thread as to what to expect, I'll be running the engine on various fuel mixes, glow lit, not lit and varying the compression ratio to see what we can learn. I'll pass on anything I come across of interest. I suspect though, that I'll just be confirming much of the great research that's already been done.

Many thanks to all,,, hey it's been over three years.

But Global Warming has become a fickle mistress. Two days ago, we had zero snow on the ground with temps in the mid 60s. Yesterday, we got dumped on to the tune of 18 inches and temps are 10 below with wind chill down to 20 below. Not gonna run this engine again for a while it seems.