RE: builder's mistakes
Dude it takes like 5 mins to switch out batteries and a switch. I dont see how complex a H9 260 can possibly be? I mean even if you go nuts on a 28% plane you might have 3 batteries right? 1 ignition and maybe 2 for the rx.
So it goes battery to switch, switch to regulator and from regulator to RX. You do realize a lot of other people have been running regs with non lion batts to keep everything consistant for a long time.
Fwiw I flew a plane wired the "wrong" way when I was first into big planes and it didnt crash. So long as your RX gets the juice thats all that matters. If anything your batteries drained as a result of being hooked up to the regs.
If you run miracle switches you had better disconnect them from your battery or they will drain.
All poking aside this is really something so small and easy to fix. I mean I think wiring an RC car is more complex in than wiring a battery, switch, and regulator. Getting a new plane would be like the extreme.
If you go this crazy with the wiring man then wait until its time to mix the gas for the DA and set the carb needles.