Thom, I own a variety of vintage bikes with betors, marzochis, honda,husky, etc. forks. To make it easy on myself I use the oil height method with name-brand fork oil, say 15wt. for starters, at 6-61/2 inches of air gap from the top with the springs removed and the forks collapsed. This way the level is always even between the two tubes and can be checked between rides should a slight leak appear. A suction tool is easy to make with a squeese bulb and clear tubing. Good luck.