That is now used as an alarm for me, after making a street light like style pole out of PVC piping, it now hangs right over where I sleep just about 5 inches from my face.
If I had a setup like that, the thing would end up flying across the room .lol.
Not even on purpose or from it turning on ... just a simple matter of it being way too close & me moving around.
Maybe I should get some HO 48" tubes and put them in, that will tick her off the most!
Unless you changed out the ballast, it'd still be the exact same brightness as with the F40's (ie: around 25w/lamp)