Here is a great guide to setting up the CH throttle quadrant. This is what I use, and my reverses work like a charm. Occasionally, I have to advance the throttles slightly for the reversers to close. Not every time, but maybe 3 out of 10. The 747 is friendlier than the 777.
http://www.uk2000scenery.com/fsuipc-guide-v1.pdf
Pete - They say that, but I have always run my calibrations through FSUIPC on all of the PMDG jets and I have never had an issue. I set up my reversers using the throttle axis’ and, just for fun, I have my extra throttle that is built into my yoke running the reversers as well. My CH throttle quad gives me nothing but full reverse, but if I decide to use the spare single throttle on the yoke I can pull it slightly to activate idle reverse and continue all the way through full reverse. The whole range.