Mike,
Thanks for sharing your experiences with 510 Pyro. I too use 510 Pyro along with P-TEA when speed isn't as much of a consideration. Your development times as stated look about right. I work with both MF roll film and LF sheet film. Printing on fiber VC with an Omega D2V condenser head and the Radeka Contrast Masking system. I find this developer extremely pleasing because it displays the unique aesthetic qualities of traditional pyro formulations, with film speed and general fog (similar) to Pyrocat HD - M or P variants. The developer truly last for years if not decades while in stock solution, resist streaking, and can be used with semi-stand or even stand processes if desired. I would never argue that Pyrocat HD and its excellent line of variants are either inferior or superior to the 510 Pyro formulation, but certainly in the same league of excellence in general with each other, each being unique in character. From my perspective its more about my aesthetic response to the developer and final print, than quantitative analysis, since my interest is more empirical in nature than some may gravitate toward. Having stated this position, I have used either 510 Pyro or P-TEA several hundred times since their inception and feel very comfortable with their use. If I really need a speed increasing formula then I migrate toward GSD-10 formulation. Each of these formulations and blog comments pertaining to them, can be found on Jay DeFehr's website: http://pyrostains.blogspot.com/ Please keep in mind, that Jay as of recent, isn't able to respond to comments for personal reasons until further notice--respect his privacy please. So you'll want to keep this in mind if you intend to post a question on his blog. He has however, provided a very informative site, with plenty of information on all of his developers and technical use. Jay is a great guy! Of course, those of us actively using organic solvent developers have much appreciation to give to Patrick Gainer and his monumental research on this matter, and kindness to share with us "backyard mechanics" in classic photography.
Cheers,
Mark Booth