If 10 people respond to your question....You'll get 11 different answers
The Instruction Book that came with the car says...
For average driving, the spark lever should be carried about half way down the quadrant. Only for high speeds should the spark lever be advanced all the way down the quadrant. When the engine is under a heavy load as in climbing steep hills, driving through heavy sand, etc., the spark lever should be retarded sufficiently to prevent a spark knock.
Those instructions give a lot of leeway. Also, no two cars are timed exactly the same, and no two cars have exactly the same wear on parts like, distributor shafts, distributor cam, points, cam shaft and cam shaft gears, etc. Also, setting points with a feeler gauge is prone to error no matter how good you think you are.
Start with the above instructions from the manual and play with the advance lever at different loads and speeds. You'll find the sweet spots. What works for someone else will not necessarily work for your car.