Occasional starting difficulty with Digital HP CD box in my D200

This past weekend I redid the engine-to-frame ground, also cleaned and added some conductive paste (copper anti-seize) to the starter-to-bellhousing bolts thinking that wasn't grounded well. The starter turns over a bit faster but the voltage drop when cranking still seems to be pretty high. I also bypassed the bulkhead connections for the ammeter and alternator charge wires a couple weeks ago, that improved some other things (brighter lights, amp gauge reads more steady) but didn't fix the issue.

I'm going to check the rest of the connections in the starting circuit to see if there's something funky going on. I'm likely just going to put a relay in and have a wire coming straight from the battery + to feed the ignition box "on" wire and also the sensing wire for the voltage regulator. I have a feeling the new ignition switch I put in the truck a few years back wasn't good quality and has some resistance in it.