Happy to say that with all the great content here in the forum I removed the selector box, disassembled it, marvelled at it's workings, cleaned it, installed the Scud spring, surfaced and polished the pawl arm, put her all back together, put it up on the bench vise, and started walking through the selector positions. Eventually settled on about 1/4" turn adjustment to the eccentric in order to get more throw on upshifts. Seemed like the pawl arm wasn't easily getting all the way ramped and over the selector roller. Reinstalled it dry to the bike and put it back on the garage floor. Rolled it through a few series of up/downs through all the gears. Seemed good enough to follow on with sealant. Hoping for no oil seepage tomorrow.
One bummer ... the two vertical Allens immediately adjacent the starter (furtherst left on the box) have very weak thread engagement as if they're stripped, which makes no sense. Seems par for the course, though. Will enjoy getting a few rides before the weather turns and then the decision to keep her or not.
My thanks to those that delved into these issues long ago and took the time to pass on the knowledge. Diving in there was a little initimidating, but once in the midde of it and solving problems, quite enjoyable.