Never easy.....
For 900 RPM engines Hot at 0.012"
For 1200 RPM engines Hot at 0.016"
2U 7129-up has a full load rpm rating of 1000 RPM
The 13A is a 1200 RPM engine
Add 0.002" if set cold.
Thank you Old Magnetic. Seem to have a lisp that comes and goes?