Setting timing on A.

My I&T shop manual states that timing advance kicks in at speeds above 200 RPM but since low idle is 425 RPM and I can't get the engine to run at 200 RPM without stalling right away. What is the best way to check timing? I only have a plain timing light, should I get one that has a advance adjustment since by 400 RPM the timing is already advanced by 9.5 degrees. That way I just dial in the advance for the RPM and get a accurate reading without fighting the motor to run at a ultra low speed?

Assuming a distributor: Static timing is used to set the initial timing. Set the point gap to .020". Under the flywheel there is a hole that allows the viewing of the timing mark. Assure that the #1 cylinder is on compression TDC (cylinder toward radiator). Put a circuit test light on the distributor side terminal and a ground to assess the voltage there. Loosen the distributor at the flange. Turn on the ignition and rotate the distributor clockwise (looking from the rear) till the light goes out. Then turn it back CCW till the light just comes on (points Break). Tighten the clamp, and shut off the ignition. The engine is now timed pretty much as it is designed to be adjusted. A small amount of advance can be dialed in if the starter doesn't kick back, and no Spark Knock happens. DO not do this if the engine is hand cranked, it must be at TDC.
If it is a mag, the mag should have its points set to .013". The mag should be turned in the same way the distributor is turned so the impulse coupling does not trip as the engine is rotated to TDC. This sets the impulse coupling to cocked position as the engine is set to TDC. Now rotate the mag CCW till the impulse clicks. Lock it down. and it is now set. There is no Centrifugal advance on the Mag, it goes to max advance when started. Jim

You could time it by ear.

Set throttle at max, then advance timing until it slows a little, then retard through max speed until it slows a little, then set it in the middle.

Your A came with a mag you didnt say if its a mag or a dist if you have a dist the advance mite be messed up you would time a dist a little advance then check the advance as it speeds up

Time it the way Jim explains.

My A has a dist with a electronic conversion kit. Never had a mag on it as far as I know. Maybe the old owner changed it out?