As for the overheating... I suspect now that it was the timing, though I had it set at around 17 deg. at idle, a setting I'm pretty sure I was cited.... somewhere..... Anyway, flushed the system, put in a new water pump (though the old one looked OK, no deterioration on the blades, etc.), put the mechanical fan back on (I had taken it off when I added the eletric pusher fan) for a little extra airflow, set the timing at a lesser advance (around 14-15 deg. at idle). Had to drive back to NYC from RI so left the thermostat out for the ride and now the engine is running cool, so the new thermostat is going back in. Things pretty much seem good now, though I can't for absolute certainty say it was the timing alone that was the culprit- I also put a new exhaust system on and cleaned and reoiled the K & N filter on the carb, so several variables changed.

Could also be a little slop in the dizzy (gets a rebuild when I install a crane system next), or maybe the marks on the pulley are off, putting my timing off when I set it last fall. It wasn't pinging at all AFAIK, but hey, things are working now!