Thanks all.
Sloping tube frame bike? I'll die on the road first
The downtube shifting has become more a mental than physical issue for me. I used to have no fear of crashing when I was young and invincible, now I don't like taking one hand off the bars, especially when the bike's loaded down with panniers, tent, sleeping bag, etc. and is less than stable.
And truth be told, it is an awfully tall frame, and getting the leg over is becoming tougher.
So I see a couple of options:
Find a Sachs new old stock (NOS?) 7 speed freewheel and use 2x7 brifters, relying on the derailleur stops to keep from jumping off the freewheel on one end or the other. I assume I'll need a 7 speed chain for this? Is the 5,6 and 7 speed chain all the same? (BTW, if the Sachs 7 speed freewheel is the same width as a old school 5 speed freewheel, why did you even bother to take of the other two cogs rather than leave them on?)
Upgrade to a 7 speed drivetrain, but what is this 126 vs 130mm measurement? from the inside of the dropouts? I can use a caliper to measure both dropout-to-dropout and axle length. Is that what you're talking about.
And I checked out Microshift and they don't show a friction brifter, though they do mention bar-end shifters, which a a classic option I guess I could go with in lieu of brifters (my first real bike, a Raleigh Super Course, had bar end shifters, but that bike got stolen while I was in college, ergo the Nishiki).