Hi amigo,
I have started out with 1 ViparSpectra 600W Reflector Series (cost 169$ 1 year ago) they consume 260w and yield me about 100-200g per run.
I have upgraded to 2 ViparSpectra 600w 1 Lamp per 1m². In 1m² I grow 6-9 plants in 7L pots. Each plant gives me 20g at least.
I started off with a sativa-hybrid (Jacky White) and always had problems, fluffy buds, odd looking etc.
Since I have taken this strain out and replaced it with some Royal Queen Seeds genetics (Royal Cheese, OG Kush, Critical, Bubble Kush of which I can recommend all except the Bubble Kush) everything is perfect. If am about to yield 1 lamp this week, if you message me I can show you a picture in private so you can see what to expect.
(20g/plant is my calculation and it seems to work, I have not had a chance to get exact yield measurements because I always smoke and give it away before everything has dried.. sorry)
Hopefully this helps. I know a lot of people talk a lot about ViparSpectra but all my friends who have been smoking for many years, some for decades, have no complaints.
Good luck for you
PS I dont agree with the american way of growing big and trained plants, I think overall it yields you less if you only have a certain amount of space/light coverage.
Ok I just read you decided to go with quantum boards.. I myself have invested into Amare SE 300 for christmas. Hope to get the lamp soon. If you are willing to wait I can report you exactly how much better it is then my vipars