For my SS, I have used Procon pumps and still use Grundfos. Pressure at approx. 150# to 180#
"I'm considering increasing the pressure. So If I'm using the reject water in the automatic there's not really anymore expense except a little more water and in reality it's still a lot less water than the hp soap or rinse. Am I thinking correctly?"
Are you increasing pressure to SFR only or for all the cycles? If you increase for all the functions, depending on your system, the timing for each cycle will need to be reconfigured. Automatics are set up for a set pressure with a set cycle time. Slight changes can change the whole wash operation. If the change is only for the SFR you might be able to get away with it. If at the end of the SFR cycle the cycle changes back to soap to fill the pump and be ready for the next cycle your customers might get a speck of soap at the end of the wash.
On my automatic I have spot free going thru the HP pump with a pressure reducing solenoid valve at approx. 350#
hope this helps