I really dont see the point of buying a 150 watt light only to turn it down, just because you can.... WTF?
Raise the light if need be.
The ts1000 ( as I have tested puts out 550 PAR at 24 inches.
Start seedlings at 48 inches...and lower by 6 inches every week.
Then keep the lights 16 inches above .
I've always imagined, and correct me if I'm wrong, that given the area is so small there is more light hitting the plant in general. Putting the same plant and light in the middle of a 10x10 for example would have quite different results I'd think?