I haven't read all 24 pages to see if this is covered or not, I'm sorry if it was.
How will this marker perform in the cold. Living in Northern Lower Michigan it get's down right cold and most spool valve marker do not like it. Adjustments to dwell and pressures often fix the matter. I've seen people venture away from the spool valve just because of this, get a rental or borrow a marker instead. Me I love spool valves and will make the needed adjustments when I can get out there.