A previous owner had soldered a hardware store-type terminal from the stator's ignition coil 1 copper winding to the coil's mounting screw for grounding purposes. I removed this and soldered the copper wire to the little square tab on the coil's inner curve (where all the stacked pieces are). My solder spilled off the little square tab and onto the stacked pieces behind it. Could this be causing my no-spark issue?

flic.kr/p/2pLJ4cY
 

Short answer No, wouldn't be an issue.
So other end of that coil goes to the points--or condenser & points?, so long as they all meet up somewhere & via the black wire end up at the plug coil under the tank.
What reading do you get from that coil. Won't be much, like under 2 ohms guessing.
Trying to think how to do that without unsoldering or disconnecting but i guess? that if you bridged the points with something non conductive then lift the condenser off earth you could hook your meter on low ohms to the black at the loom out of the mag with loom unhooked from main loom.
I write confusing.
MarkT can sort me out please if i've mucked that up. All good.
ps one lead to stator plate of course & other to black.

The stacked plates are supposed to be isolated (insulated) from each other for maximum output.  So you don't want to short the plates together.  Often the ground is a terminal under the screw. 

Per someone's idea in this forum, I taped together 2 "D" cell batteries, took positive and negative wires from this battery pack, and put negative to the steel on the bike, and the positive wire I scratched on the condenser top that has all the wires soldered there (key was on) and got a spark from the spark plug. So, correct me if I'm wrong, but this tells me it's not a key-switch issue, and it's not a ignition coil issue, right? So, that leaves what? Maybe the points are grounding out somehow?

Or the points are not making good contact when closed?  Were the points open when you did your scratch test?

They were closed. But! It did take a little effort to get that spark. I thought maybe I wasn't holding my mouth just right or something, but you're saying it could have been that the surfaces of each side of the points' nodes aren't exactly, perfectly flat? Causing sometimes spark, sometimes not?

That's a fiddly way to get spark so it doesn't surprise me it wasn't consistent.

The thing is, if you were able to get any spark with the points closed, it means your points are not making good contact.  With points closed you have a direct short to ground and it's exactly like having the key off... if the points are making contact.

Dirty points is the most common cause for no spark.  I've have people send me ignitions and at least twice all they needed was the points cleaned which they say they did? 

I don't sand or file the points unless they are really bad... then some fine wet/dry automotive sandpaper usually works.  I spray them with electrical contact cleaner.  Then I cut strips of white card stock (best is a white uncoated business card... you want something that won't leave a tiny tuft of paper behind).  I open the points, stick the strip of card through them as far as I can, close the points on the strip of card and then pull it through the closed points. 

The strip of card will have black residue from the points.  So get a fresh strip and pull it through again.  And again.  Eventually the card will come out clean. 

(If you have a burr on the points the card will be hard to pull and will get damaged...  you need to file that off or replace the points depending on how bad it is.  Unless the bike is super high miles or exposed to extreme corrosion, points almost never need replacing in my experience.)

 

Points Class 101! Thanks so much! By "very fine" wet/dry paper, what grit? 400? 800? They are new points, by the way.

New points often gain a non-conductive coating in storage and almost always need to be cleaned.  I would not use sandpaper on new points.  Contact cleaner and strips of card should be good enough.

I would say 400 grit on most used points...  the more "polished" they are, the better.  600 would work too.  But again, I don't sand or file them unless they are pretty bad.

I remembered finding an old book on motorcycle repairs, written by Bob Greene and other motorcycle mag editors of the day, that I got when I was 11...  I looked and found it has instructions that say don't pull the card out.  They say just twist it.  I've been pulling the card through for decades but I always use high quality business cards that I've collected.