Pukka,
From what I have read about like the Son Agra dual spectrum bulb those seem to work better than just the HPS for veg. In terms of efficiency and cost per to run, in addition to stretching, those are the best choice all around. The article I read says that 'those produce the tightest internode from any bulb' This was from a grow site and not a manufacturers site so sounds solid.
It sounds like you have the best bulb for all around grow so best of luck. with the 250W though you are going to be limited to a smaller area though. 2000 - 2500 lumens per sq ft is good so you should be ok with about 10 sq ft with the light not too high. Just my two cents and what works for me. I am sure someone else may have a more text book
number for you though.
Hope this helps and good luck. Let me know how that bulb works since I might invest in a 1000w for my HPS. Haha
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