It's going to be a game of trial and error. You may be able to get away with less air, but then again, 60 rides nice, that may be your sweet spot. Did you also install an in-cab controller, or a wireless remote? If not, and you can afford it, do it. You will love the ability to adjust the air pressure "on the fly".
Ed and Sharon
2010 Wildcat 28RKBS
2011 Ford F-250 XLT, 6.7L PSD
Ride-Rite Airbags and Airlift wireless remote compressor...nice!
I thought I was wrong once, but I was wrong!