I managed to be brave and ran the generator tests (they really weren't that hard). When wired up to power, the generator spun like a top. The passive resistance tests showed about 50 Ohms between D+ and ground (though not stable, occasionally went to 40 or 60, though mostly in the 50 +/- 2 range) The DF to D+ read around 6 Ohms, though spinning made it fluctuate a teeny little bit.

The only test we failed was the regulator bypass test.

Am I overreacting to all of this? Two days of fiddling with the engine running has not drained my battery, perhaps I'm just expecting more output out of the generator than I should? There are more volts when the car is off than when it's on, which makes me think its not actually charging, but perhaps this is the difference between a generator and an alternator? Does it just "top off" the battery to keep it at 12.4? I'm also confused as to why the B+ terminal read around 10.4 Volts while the engine was running.

I was worried about learning how to tune my SU carbs, but holy moly, that was a piece of cake compared to this! (although I'm learning more and more about the ol' girl every day spent under the hood, so it's not all bad!)