hey guys, thanks for the positive comments on the post, i'm glad you find it interesting, and hopefully even useful.
hey greenmachine, i tried desperately to come up with a 250w mh, but couldn't. i know it's a very popular lamp, so i'm still looking...
anyway, the 250w mh has about 59% the mean lumen output when compared to the 400w mh. so that should put it at about 1.9k lumen/ft. sq. @ 12", right about where the 25W compact fl. is on the chart. (but don't forget the 25w cf is measured at 2" - the mh is much brighter than that since it's measured at 12" - meaning a bigger garden).
you can probably squeeze a few lumen more, since the 250 mh's are available in the base up variety - using the round sombrero type reflectors - which i suspect are slightly more effecient than the half-cylindrical type i used for the measurements.
Grow On!