This credit does not allow installing T9, T10 or T12 fluorescent lamps. This credit provides a criteria to specify T5 and T8 fluorescent lamps. Are there any requirement for T2, T4 and T6 fluorescent lamps? Are we free to install any of these?
I couldn't find T4 or T6 guidelines out there. For T2, you may have to get information from several manufacturers and show that your selection is on the low end of that scale. I would not gamble that you can use these with impunity since all fluorescents allowed have to meet a criteria.