I have never seen your set up. I have read postings where you talk about your set up and also seen your testing interments readings on youtube.3 jobs today all 75 ft runs. 2 inch hose all the way to a 1.5 wand. No leader (whip) hose.
You have the right mindset , restricting air flow will reduce amperage. Ed V. did this with the 1 1/4 hoses within the Recoil cabinet. My personal testing showed no difference in performance ATM 2 inch vs 1 1/4 hoses OR motors direct to recovery tank.
Restrict your open flow . I set hose end down so it butts up to a section of the hose or ? thus causing restriction and lowering amperage. A glide will restrict some flow which I always use.
Your motors probably draw more amperage at "idle" than the 8.4s or the 2 2 stage motors as my rear booster.
I still occasionally pop breakers with the ONE 15 amp circuit that I need to run ALL four motors beside the Genny. Always the poor wiring on location usually 100 amp not 200 amp service. PITA
Do you have some photos to post on the quad vac set up with details on what specks you have on each vac and hose?