A T8 12% or 10.0 is not a bad option for Panthers. However T5HO all the way for me. More efficient and more power (cue Tim Taylor Home Improvement grunt)
There is nothing wrong with a T8, not as energy efficient but who cares honestly if you already have them. The reading is the same with a T5 as with a T8 using a solar meter. The T5 and T8 means the diameter of the bulb. One is 5/8” and one is 8/8” = 1”.