All I said was that my RW-75 requires about 8" to canopy. (The published info says 12-14".). I can put an 85w actual UFO (3w epi-unknown chips on a white diffusion board, no reflectors) about 2" from the canopy. I try not to get that close, but in a 4' tall space, 6" is about 25% of the available height.
IMO that's a factor which could justify a cheap epi-unknown Chinese import if someone's not willing to spend more on a Hans, or go the LED "lightbulb" route (or, as you suggest, get a taller tent).
We were just talking about when a Chinese import might be a good choice. That's about the only one I can think of.