Do you think It would be a good idea to mount Stainless tanks and hydrominders above the pump stand and gravity feed the HP
soap instead of the current setup.
If you look at my pics, this is how I have my pump stand plumbed. Hot and cold tanks are above the pumps and actually above the tip of the wands in each bay. I don't have any issues with water dripping in the bays. Since there is a Cv in the HP hose at the pump to keep weep from back-feeding, I think this is all that's necessary to keep water from syphoning from the tanks.
Soap and Wax have been set it and forget it. Both are drawn in the pump at 10oz per minute. In 3-4 years, I have not had to make a single adjustment and the volume is always the same.
As for overhead, I only have 4 Cv's in the attic for my 4 bay. 1 on each HP manifold for SFR...I don't have any CV's on FB, PS, and TF...Air lines are tee'd in the Er to save on space and tubing in the trough...As long as you don't get wild on the air pressure, the kip solenoids will hold back any back pressure from other bays...I also have a blowdown/washer fluid injection system on all LP hoses...No Cv's there either...