Riggsby turned me on to: https://lambretta-images.com/tuningh/port-timing-calculators/degrees-to-mm-timing-calculator/ . Peugeot has a 39.1mm stroke and 76mm conrod unless you have the 85mm conrod malossi "not-stroker but marketed as a stroker cuz euros don't know what stroke is apparently" crank in there. From there, get it started, and rev out on the stand with the timing light on it, and mark where initial fire is and where it ends up retarding down to. You can then measure the distance between these with your micrometer and get the curve, so you'll know where to set your max advance in order to retard down to a reasonable point. I like to set stuff so it retards down to 17* or 18* or about 1mm-1.1mm btdc on peugeot, and that makes total sense since that's where most people static time le partie, the but that's fairly conservative.