I've done ice and was so satisfied with the quality and vigiour. So crystaly and a bit above avg as far as yield goes. I'd say stay away from the master kush. I had two friends grow it and both were diappointed. It just wasn't very kush like at all. Have you looked at there new purple power?
I do know that an 250 hps is aprox 30000 initial lumes and 600 are aprox 90000 so my educated gues would be approx 8000 initial lumes. Of course it varies depending on the company that makes the bulb and the shroud you use.
I have seen the yellow in every iss plant I've ever done. It does look like hermie though but I would agree that it is common in this genetic. Ps this strain is amazing easy to clone and so vigorous with massive yields and so much crystals that I even use the majority of fan leafs for hash. Well...