I found a you-tube video about how to build and use a manometer to test LP gas pressure in an RV.
I connected the manometer to one of the stove burners and initially read 10"WC, but it quickly dropped to 9"WC after I lit the second burner, then even farther as I started the water heater.
I then connected the manometer upstream of the atwood regulator to test the TT main regulator, it read 10.5"WC, that quickly dropped after starting the furnace and water heater.
I found an adjustment procedure for the TT regulator and raised the static pressure to just above 11"WC. the pressure with appliances running was under 11"WC.
NOW my stove pressure downstream of the atwood regulator reads 11"WC.
time to call Atwood again, and deal with the tiny LP gas leaks in connection I disconnected to use the manometer.