Though I'm new to rving I was new to the macerator and it seemed too hard to operate. I had to crawl under the motor home and I'm old for that.
Hm. I have the same rig you do, and no 'under coach' adventures needed to use the macerator. My process is- (after getting the macerator hose ready and TAKE THE PLUG OFF THE END OF IT

)
1) open black water valve with electric switch
2) Run macerator until it sounds like all effluent is drained.
3) Close black water valve.
4) open grey water valve with switch
5) run macerator until done
6)close grey valve, rinse end of hose, put away
A bit late, but I wonder as to why you needed to crawl under. Glad your new setup works for you. The Macerator saved me driving 200 miles home with full tanks new years day. Handy port-o-let was 'willing and able' to take my load.