With the static timing set correctly modulation should be 45% to 55% at idle with engine up to temp. Maybe a tad lower than 45% with new chains. Modulation is only checked at idle.
At 128 idle should be rock steady at 750 RPM. Sounds like someone has had the top and mid sections off played with and damaged the quantity servo and not reassembled pump mid section properly. If you don't have a clue what you are doing don't do it.
Can't see how a SRS wire could be disturbed fitting a wind screen. Apart from under seat connector if the car is 1999 on. Seat air bags not fitted prior to 1999.
My view is not an opinion it is a fact. Now you lot believe what you want to, it can be done. I have had a Nanocom longer than anyone on here and I know how to use it.