I tested my Cline fuel regulator today for the first time on a Saito 1.50.
I found that the high speed needle valve became less sensitive (as stated in the instructions), but I have the impression the low speed mixture became more sensitive. Closing or opening the idle needle 1/8 turn gives me a difference between idling forever and dying from like 3000 or 4000 rpm.
My idle needle was not that sensitive before I have the impression.

Has anyone had similar experiences? The engine is still on the test stand and has about 1 gallon through it. This means it is still running on the rich side, but this should have nothing to do with the regulator.

I didn't notice much of a change on my 150 except as you said the high speed became less sensitive, once you get them set you can pretty much forget them except for big changes in the ambient temp. Also your Saito was broken in about three quarts ago, I have ten Saitos and have never babied any of them. They thrive on being used. Also, with the Cline installed my needles both stayed in the same place they were, others have said there was a big difference. I think that if a fuel tank setup was marginal before the Cline is installed there would be a significant change after.