Just a few notes on my 'sperience with the RVi2 brake, Ed:
I didn't believe that the brakes on my toad (2800 lb Kia Soul) were really doing their share, so I called the support folks there at RVi2 in Castle Rock, CO and asked them if they thought it would be OK to increase my "Vehicle Selection" from "Compact Car" to "Small SUV". They said "no problem" so I did that and I could physically tell the difference in deceleration (from 15 MPH) when I pressed the "Test" button on the remote .....which I always do before heading out. BTW- the RVi2 is a proportional device, but when you press the test button on the remote, it applies the max pressure for the vehicle setting you programmed in......that from the RVi2 tech folks.
In my case, that change doubled the actuation force (air pressure on the actuation cyl went from 5 psi to 10.) The only "test" (using the term loosely) I did was to have my wife verify that the toad wheels didn't skid on the surface there where I store the RV (that surface is made up if asphalt chips that were hauled in from road scarification in the surrounding area and then rolled out ..... so it is a bit more like tight gravel than real pavement.)
In your case, you would be increasing the actuation force by about 33 percent if you went from Lg SUV to Large Truck (from 15psi to 20.)
I should probably run a test using my IR Temp Gun, but I have towed my Kia just under 15K miles now with the higher braking force and all is well ...... no abnormal brake wear. It's been a trouble-free toad brake; the main reason I bought it was for its fast response time (approx 1/2 second) and I wanted that for panic stops ..... like yours.
I was relieved (in a left-handed sort of way) to read about RV stopping distances in Gary's response. I have always thought my Ford brakes were lousy (I recently replaced the front rotors, calipers, pads, and wheel bearings) but I actually believe I can easily stop my 17,000 lb gross comb wt well within those guidelines.) But I'd still like bigger brakes.....and wheels/tires too. lol
Safe travels to ya..........