Have you ever thought to compare your best engines crank positions to see how close they are to one another even if modified with different cranks and rod length ? Are the timing numbers way off but crank positions closer to the same ? I did and was a little surprised! The results may lead to a short hand formula to get best timing adjustments according to the crank position when experimenting with rod and crank size.
Is it possible that cranks end up very close to the same position and if so how can this information help us or not ?

Also trying to find info about crank speed restrictions when piston travel meets up with compression and crank case vacume / intake suction during a revolution. Does the counter weight play a part in helping deal with those revolution restriction.

When the exhaust port closes the rotations momentum is reduced thru compression travel distance before combustion. Mods like the transfer ports opened up, piston is lightened, use big carb decreases restriction and faster momentum is achieved. Power was not added the components were just allowed to move faster and make more momentum force. The timing adjustment are referred to as being raised instead of advance or delay. When exhaust port is raised the start of compression is delayed, crank angle timing changed, compression distance is reduced and combustion energy is lost. Cut the base to bring everything back to were it was and the biggest difference is the reduction of combustion travel distance. Was the crank timing changed if so by how much? Can you really say combustion energy was increased or did it simply achieve the same combustion energy in less travel distance perhaps without changing the crank timing angle. Intake vacume travel distance is also reduced the way port and skirt are cut. I think we should ask our self is if these engines are creating more force at the prop is because of increased combustion energy or weight force energy. No question that by reducing compression tavel distance , maintaining proper crank angle timing will increase momentum. The higher the exhaust timing the lower the squish. The ignition timing is pretty much a bone deal but the crank angle before ignition is up to you.