I see 60-65% eff all the time in my brewing and that's why I ask the homebrew store to crush my grains twice (they're nice enough to do it since we're all living in apartments here and almost none can afford such luxury as to have grain crushers or store sacks of grain at home) after which it goes up to 90 sometimes, but generally hangs around 75-80 for mid-grav brews. I'd love to get an even finer crush, but there is only so much that can be done in these conditions. Perhaps I misspoke... It generally takes me about 30 minutes to get the first runnings to the stove and do the rest of the mumbo-jumbo before I get to collect second runnings, so that's why my magical number is 30 minutes. Indeed I cannot see any possible boots in conversion with a mashout+second water since it denatures the enzymes, but I think it does boost up the solubilization and results in my observations. Anyway, I'm not saying "convert or die", just stating my observation and what works for me because it seems to be somewhat tangent to the topic of this thread.