Twinmax carb sync tool
 

Want to compare experiences with another member who has used the Twinmax.
Last weekend I used it and want to see if my experience is typical of the tool.
Already had the plumbing set to go, so hook up of the tool was no issue. Set the zero per instructions and started the engine. Needle was dead center. At full sensitivity the needle was bouncing to the engine pulses equally on both sides of zero. What is confusing to me is I pressed on the rear carb sync screw a little, enough to get RPM rise, but the needle did not seem to indicate any change. I seem to remember turning the sync screw a bit with no change in the needle. I also pinched one of the lines going to the Twinmax and until I really folded in half did I get an indication on the read-out. I would have thought that even a small restriction, like pinching the line with my fingers, would register a big change. I got nothing doing that.
Maybe I was high on exhaust fumes. I'm going to try it again today and see If I can get similar results and take better mental notes of what I do.

I presume you know where the sink screw is and it was warmedup and the sensitivity was turned up as much as possible

Engine was warmedup. There are a lot of screws and stuff that seem to do different things, but the illustration in the service manual is clear enough that I'm confident that I got it right.
I would have preferred that the carbs were out of sync and I had to dial them back in. I wouldn't be doubting the veracity of the tool that way.
At full sensitivity the needle bounces too much, but there is a point below that seems to be a good compromise.