@DPA200, mine is similar but on the left side.
I may eventually go with the Redarc. Occasionally I want to adjust the brakes - seems like when they warm up they are more sensitive than when cold and while mine normally work great when I've been in the city for a while they seem to warm up and then lock up easily. Adjusting the IQ requires me to lean and reach down, which is inconvenient if not also kind of unsafe.
Yup, I get this too. Seems to be the nature of trailer drum brakes.
First couple miles, my trailer brakes are soft. So I dial my gain to ~12.1V on my Prodigy and Airstream combination. After some brake applications, the brakes become pretty aggressive at that setting. So I incrementally back it off to ~11.5V. On the Prodigy P3, it's a simple one button up/down arrow adjustment. The readout allows me to know the specific gain setting and if the trailer brakes are working as expected.
I so want to do the Redarc for its slick interface, but don't want to give up the nice feedback and diagnostic functions of the P3.