</font><font color="blue" class="small">( I'd rather use the battery to start the tractor, than use it first to heat the glow plugs.)</font> Any particular reason you prefer this approach?
I do it somewhat similar to Bob Young,
I like to have it start on close to first revolution.
On one of my diesels, I use year around (unless the engine is already warm) or it takes 5+ seconds of cranking before it starts, even if it's 90 degrees outside.
Another diesel starts on the touch of the key down to about 25 degrees. (then I use it)