Timing the 30 model A engine

[30standardcoupe]

Is there a step by step on how to time the model A engine? My engine runs pretty good, but it really lacks power at top end and backfires when shifting gears. My advance/retard lever is in the full advanced position.

I have seen on youtube where a gentleman made a pointer and used a timing light, but how do I know where to set the timing or what degrees?

I am familiar with V-8 engines, how to disc the vacuum advance, and such, but the model A engine is my first rodeo, so if you have advise on how to get the timing really close please share.

TIA
Clay