Never had Raven, Never installed Norac as it was on a used sprayer I purchased. Have 5 sensors on a 120' Boom. I would think 3 would be okay on a 90.   Always has worked well for me. Soil mode is good and crop mode works good on soybeans when spraying for aphids. Keep in mind it is only as fast as you can operate it manually. I would say I wish mine was a little faster, but I would need bigger hoses going to the lift cylinder.  Calibration and using it is easy.