Shit man, fab two more relay sets, put a blue top optima back there too, and ya kin make the side winders go up and down like a hip-hopper!
Nice workaround, no doubt that concept is how these under-ampacity IH rolling electrical fireballs shoulda been done from the git-go!
Don't go lookin' for any more relays on these junkers...only the horn had one! But iirc, that rear winder uppee/downee switch is a 50 amp version but the wiring is only good for about 8 amps in that long a run.
"some" of the rigs with factory a/c also hadda add-on relay for the compressor...but not all.