I wish I could think up a better title to this thread to get it to show up in the most internet searches on the subject of old, sluggish shutters. You know--the old lighter fluid trick; naptha, paint thinner, or your favorite potion. Well I have news for you: say you've done the lighter fluid trick and have got your shutter nice and snappy again, and you're happy.
Truth is, NOT A CHANCE. It's nowhere near accurate, I promise you. And if you go off and start your film speed and development testing based on that shutter, and reporting your results on these forums, then you're totally polluting the information supply. And your tests will be so fouled up, a good actual photograph will be 75% luck.
I performed an experiment and sat here for hours testing press and view camera shutters, and you won't believe how far off most of them are. Of note, I've got a Compur here for a 135 Schneider from a Graphic Special. Absolute mint, never-used condition. And every speed on it is nearly exactly 1/2 as fast as the dial says. That means whatever film you thought was ASA 100, is really ASA 50.
The moral is, to either make a shutter tester from the photodiode of an old computer mouse and find out what your speeds are, so you can paste a chart on the camera, or send the lens off for a proper CLA.
Good luck.