"Some folks don't want to crawl through the firewall to the ignition switch for power...the coil location is handy."
Why not just run it from the switch and save yourself the trouble of installing a diode? Seems to me wiring it to the coil is just cutting one corner and diving into some extra work.
"A small dash lamp can be installed in series and it will supposedly give enough resistance to negate any run-on problems when DA #1 is attached to the coil +."
I don't think the resistance of a dash lamp will stop power to the coil. A dash lamp can be installed in the wire from the ignition switch to the alternator. When the switch is turned on, the lamp will illuminate because it is grounded at the alternator. When the alternator kicks in there is 12V coming from both directions and no ground, thus the light goes out. When the ignition is turned off the engine dies.
If you wired the alternator to the switch you don't need the lamp but one can be handy as an instant notification that you've thrown a belt.
