"Try 70-90 lumens ... for most FL's."
My original assumption was a bit lower than that. However, when I
started checking with local aquarists, I discovered that most
were running 18-24" T12 lamps which are less efficient even when
new. I also discovered that most replaced their lamps only when
they failed, which cuts lumens further by typically 20%.
Hence my request for real data on a broader scale than one local
club.
"(a poor measure of PAR BTW) "
I agree - see
http://sankey.ws/plantlumen.html