So if you had a decent reflector for T-12 what would you guess the increase would be.
Not sure there's a valid reason to use them anymore but having used them for 25 years it's like losing an old friend. lol
I think you might gain another 30-40% if you used a somewhat parabolic, highly polished aluminum (MIRO 4) reflector, that was big enough for that size bulb. That would barely be a significant increase.