Gene, I am not sure if I am reading your post correctly but if I am, I would not trust any machine over 4gpm for direct supply from the garden hose. Just too unreliable from too many locations. I have tried it a few times in the past and really hate the cavitation vibration when the supply is not enough.
I run it all from the tank.
All you need is really at least 3/4" or 1" line to each machine. The block valve at the tank is what I do in case I need to work on the machine.
Since I have an 5.6gpm, 8gpm and a Bandit, I put 2 of the 2" "T"'s on both bulkheads of the 125 gallon tank and use a 2" to 3/4" reducer bushing and run the 5.6gpm and Bandit off one of the "T"'s and the other supplies the 8gpm and a hose going off the side of the trailer to fill buckets or wash hands with a ball valve right there. It is used on just about every job.
I just run 3/4" hose from the tank to everything, no problems ever. Just do not use soft or weak hose as the pumps can collapse them.
Since I have 2 machines on the trailer, I have 2 float valves on the tank so I do not overfill the tank and flood the trailer. Most of the time I am using one machine so one supply hose is good but if I run both machines, I have to run 2 supply hoses.