how maney watts of hps light can I fit in a 3x6 room before im waisting it ?

???

Its more the issue of how many watts you can keep cool in that small space...how high is the ceiling?

How about a big led fixture and no thermal issues to solve.

8 feet with a 6500btu ac at the moment

two - 600's if you can keep it cool me i would run two 1000's with fresh arctic air coming in non stop "_"

I just got a third 600w to throw in there, so that will be 1800w, ill be doing sog