can answer all those.
1. Yes but no good results I know of, seen two used on one plant not very good results, plant was big but scraggly, just not enough power.
2. Can you go a photo with a hs1 will it work well? Not that ive seen. You need way more power that 75w unless you are micro growing or wants skinny girl plants.
3. No you will need more light especially running multiple plants
4. To my knowledge no one has compare the claims that the 75w Hs1 can compare to a 250w Hps. Dont think it will happen either.
5.yes you can change the settings but you have to the extra "modulator" which I don't know one who has one on site.
..... I have 2 GN HS1.1 lights and above comments tallies with what I have seen. I also have an assortment of Marshydro, Topledseller, xmaxdiscount, Vipar, SunSpect et al, from 180 w to 1200 w and all with 5 w diodes, and given all of them produce, easily, 1g/w when asked of what I'm told is excellent potent weed (that's when I don't fool around with milk powder and such, see my sig links for more lunacy) I have a hard time persuading myself that paying more than 0,25 Euro or USD per watt makes sense, except for "special" lights such as small corner lights, strips and bars...... And shear indulgence!
Power consumption is a main concern for me, what with that new fangdangled meter that homes a SIM card.... And like others I think the GN lights has a maybe, at best, possibly 25 % advantage on slapstick named generic Chinese lights, read LG-LED..... But at a cost per w some 25 times higher and GN is far from being exceptional in the crowd of..... Ermmm..... Top tier manufactures annointed such by cost and hardly any true independent side by side comparison grows under identical controlled conditions...... Enough, Nuff said!
There is such a thing as shear grunt IMO, never bloody mind the spectrum brouhaha that's possibly merely a perception..... I haven't seen any difference so far...... When it comes to those there sparkling frosting, dripping pistils, exuberant trics, happy-go-lucky resin, juggernaut fragrances, outlandish HIGH-handedness, granite boobs, unseemly fruitages and similar such...... That is!
Hmmmm, with this being said....... there will undoubtedly be more lights like, GN (their new range coming out over the next 1-4 months, yeah right, sounds interesting), GROGLO, Illumitex and a few other American brands if only I could lay my hands on them.....passing through my hands and whatever new kids on the block with the right stuff may emerge ..... Since, in this deplorable selfie age, when was a little indulgence frowned upon and not enthusiastically embraced....... Especially if it's expensive, more is better, and thus eminently worthwhile to tangle with.... You never know what might happen..... Right?