After much research here and elsewhere (and some questions which some of you generously answered), I finally pulled the trigger and bought my first vintage, a circa 1950 steel automatic caliber 351 bumper, an homage to my late father's 1949 Seamaster (when I see his exact model in perfect condition for a great price, I'll get that too, but meanwhile ...) on ebay. BTW, no more ebay for me, I look forward to buying the next one from one of you. Too many watches that aren't running well or at all and need G*d knows what repairs, frankens, fakes, refinished dials and over polished cases, etc., and worst of all, a cast of hawks ready to pounce on any halfway decent buy. (Yes, with hawks they call it a cast.)
Anyway, now that I have the watch back from service, a shout out to Daniel at Watch Repair & Co. in NYC. Reasonable prices and good, prompt, friendly customer service. Had a 31.5 power reserve when I got it, runs 37 hours now, and Omega's specifications for this movement say 36 hours. Zero seconds gained or lost in the first 7 hours, I'll have to see how accurate it is in the next couple of weeks. But a major improvement in any event.

 

OK, after a few days, it's still dead on when fully wound and on the wrist, losing less than a second in 12 hours. Taking it off and letting it wind down, it still lost only a second after 8 hours, but slowed a lot after that, losing over two seconds per hour for the next 14 hours or so, then slowing some more. Not up to Planet Ocean 8500 standards, but I think still pretty good. For you vintage mavens, is this reasonable performance for a 1950 Omega bumper after an overhaul? I'm fine with it, just want to confirm I got my money's worth.
Edit: Sorry if this is a stupid question. This seems like outstanding performance to me for a 65-year old watch that probably wasn't well cared for. But I want to know what to expect if I get a more expensive one next time.
Edit no. 2: OK, looking at discussions on this topic in this forum and elsewhere, it looks like the range of opinions is too wide to be useful. I guess the answer is, it's good enough if it keeps time well enough for me. But I'm not going to spend real money on any vintage watch that isn't keeping time within a minute a day, recently serviced or not.