I think it's better to get a smaller lamp and have perfect temperatures and conditions than have a fuck off big light and all the conditions wrong.

You will not be dissapointed with a 400w and will be more than happy with the 600w but if all factors aren't covered (good airflow/ventilation, tempratures, soil medium etc) then your grow will fail.

I used the basic blv son-t and am more than happy with it I don't think IMHO and talking to other more experienced growers that the dual spectrums and high output etc make a huge difference.

It's your first grow dude don't get bigger than your own boots start small and if it goes well you can go bigger and better,