Wizard, do you suppose we are the only ones to install the compufire on a V so far????
I feel you are on to the reason for the high drain, but I have not done your R/R test yet. I am happy to follow your lead on this, but if you need me to do something, I am willing.
Like I said, not what I prefer to do but, I don't see an easy fix, as to battery tenders, I have worked with various batteries over the years, some of the newer chargers will work wonders, but at a price< my son replaced his Japan battery for his Honda 919 with a Chinese battery, whopping $56 new. He got a little upset because the 1 amp deep cycle charger cooked his battery, that happens with any charger, there is always a small amount of gasing, deep cycle charges and then discharges through usually a led.
If you want to prove this problem for yourself, I am assuming you cut all the wires on the new regulator , including the ground? Or did you bring the ground up to the frame ground?
If you cut all the wires, I traced the Canadian wiring diagram, the regulator ground picks up the starter relay coil wire before it goes to frame ground. Simple way to prove it, is to remove the frame grounds ( they are located on the same side as the self dia. test plug, just to the rear of this, same place as your rear right signal light exits) and find the one with 26 ma on it, re-attach all except this one, try and start the bike, the starter shouldn't pull in, providing the US wiring is the same. By the way you will need to reset the clock when you do this.
I guess a cheap fix would be to put a wing nut and stud in for a separate ground, remove the seat and lift the ground off, when done riding. I know for myself, I will put a relay in , the time to go and get the relay, plus gas, is more than the relay is worth. I could also get it from Newark Electronics, about $3, but the shipping is too much.