The real test isn't when you are diddling it by hand, but what it does when the engine is running. The manual has the specs for advance at different RPM and you should make sure that it is hitting those advance values, that it is steady, and that it is returning to the proper setting at idle.
The other thing to check is slow cranking caused by too much advance on a hot start. That means that the springs are not pulling the counterweights back to their proper position when the engine is shut off.
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe