A good way is to check the dipstick reading at the next oil change. I have a IO-360 with several different marking on the dipstick. I add at 5 quarts. Drain the oil change the filter. Add 5 quarts, test run the engine and let it sit overnight. Check it the next morning and that is my "ADD" mark. I then add a quart and that is my "6 QUART" mark. On a taildragger the oil will be higher on one side of the dipstick than the other. Pick a side and stick with it.
Calibrate your dipstick to your particular installation. You may have to re-mark your dipstick depending on the one you have. Fill your empty engine with 2 quarts at a time and mark or check the existing marks until the engine is full (usually 8 quarts for a 4 cylinder). There are lots of different dipsticks out there. Mine came from the right engine of something.