I'm running two tubes. They tend to concentrate the light a lot more in the middle, so I removed the inner reflector, which helped.
Just discovered a light leak with one though. The ducting had come away, so just the faintest of daylight was running back down the tube. My fault; not the tube's.
Once my house guests leave, I'll post the sorry results in my journal
Talking of house guests...they seem to be sleeping all over my living room, so it's off to do some work in my studio and let sleeping dogs lay...
Peace