Thanks to everyone for their help and Dave many thanks for that extra information that certainly clarifies things.
Anyway the outcome was that I really got no more oil out of the sump than I should have, maybe 1/8 pint. I primed the crank again, ran it and it all seemed fine. I also checked the timing with my strobe light, in the course of doing this I found the oil in the primary to be level with the bottom of the round alternator cover - is that where it should be?
Anyway I'm think I'm happy with the oil issue. I will pay better attention next oil change to quantities etc.
I was having some problems with the oil pressure light flickering at idle when hot, which had me more than a little concerned. I'd hoped fresh 20/50 oil, instead of what seemed like something a little thinner that came in the bike, might do the trick - but no improvement. I bought a mechanical oil pressure gauge for $19.99 from O'Reilly Autoparts, the fitting went straight in on the motor and I routed the tube with some cable ties up the frame and fixed the gauge bracket to the handle bars with some cable ties, as a temporary rig so it would be easy to see while in motion. This showed I had 78 psi pretty much by 2000-2500 rpm (and all the way up the rpm range beyond that), with 37 psi at 1100 rpm and 25 at 500 rpm with hot oil. That made me feel much better, so it looks like a new oil pressure switch is needed. The gauge was worth every penny, as it showed me what I was anxiously wanting to see.
Incidentally, I also filled it up with fresh, no ethanol gas, I don't know what the PO had in the tank or how long it had been there, but the bike ran so differently today in terms of power and smoothness it was like two completely different bikes. When I first rode it I was a little disappointed, but today I must have had the biggest grin on my face, if it wasn't for the cold, I'd still not be home