The 2-70 is really nice- still almost dies when you throttle it way back (sticky plunger?), but it is a very handy tractor!
I'm afraid you were right on the 1555 clutch finger adjustment :-<, called Maibach this morning, talked to guy in service , he said they usually need to adjust them beyond what my clutch paper said to get them to work right in these tractors... Don't have time left to mess with it now, so maybe this winter I'll get back to it.