Put a camera there so you can record while actually turning the key. Alot of times there's an initial rush of bubbles that can be missed by the time you get back to the IP
Seems to me you're avoiding the obvious. Put on the clear return line. Acts like it's clearing air out when it's getting started. You've been asked to multiple times.
Termination dust is what falls in the higher foothills reminding us that summer is over and winter is here. We don't really have much of a spring or fall
On my 94 I went directly from the battery to that distribution block with a 4 gauge wire. Battery voltage gauge is much more accurate now too. No fusible link either
On a 92 there should be a wire that goes from the battery to the starter and then up to a power distribution block on the firewall kinda above the starter. I'd be checking that out.