The coolest water methanol injection setup I've ever seen at was at Scott Countryman's shop, Destroked. He'd put a Cummins in a Ford truck that was using a water injection system from ATS. I don't recall seeing it on their website as part of the Waterboy kit. What this truck had was multiple solenoids that would send water to each larger injector. So the advantage was to barely sip at low boost levels and have plenty at WOT and be just right everywhere in between.
I've been contemplating someday doing something similar with my system. I still love my Coolingmist Vari-Cool controller but have had to upgrade to the Snow 220 psi pump. I see Coolingmist now has a 500 psi dual pump kit. Only time I've had a problem with my current system not working was when a boost line had come undone. To mimic that solenoid system with several injectors, I'm thinking of still using just the two different sized injectors I now have, but perhaps putting a check valve in line for the bigger injector so the smaller injector gets water first, then the big one. I really like how the Coolingmist injectors can be threaded and installed from the outside of the pipe, don't have to worry about the nozzle coming off inside the pipe. But if you don't have gauges, Snow's kit has that.