Your system is a doable alternative. However, while you are starting the truck on a cold day, or any day, you are getting a heavily reduced voltage to coil/points because the starter is drawing so much volts/amps. You are running the points thru the a resistor/voltage reducer while starting right when they need a snappy spark. If that does not cause any problems you are good to go and a lucky man, so far.
Whoever wired your truck was, as you say, a tractor man. Not done that way on trucks. You are messing with mother nature and father time will catch up to you.
There is only one right way. The other ways are wrong.
