you can flower under a t5s with great results, some get better results then others. I will flower under my t5s but only in june, july and august. i only run auto in the summer though the reason is cause i usually run 4 open air adjust a wings and i can keep it cool i just have to run a 15000 btu ac along with my house ac cranked up and that ends up costing me about 800 a month not worth it to me. so that is when i run all those fucking autos i get for free from my seed bank orders etc... If your going to do it i would for 1, keep them as short as possible. then i do a sea of green style with all donkey dicks(no toping) cause the t5s dont penetrate the canopy very well so i also lolipop them (cut off growth below canopy) doing that keeps buds a little tighter and you can focus more effort and energy on the central cola and 2-4 of shoots. I also run a mix of warm and cool bulbs in my t5s when in flower . so it is really up to you if you have the t5s you can have a good harvest would i trade in my 4 1000ws, not yet, but.. you can still get a good yeild i just dont think resin production is as good, but for the money you save its sometimes worth it. my friend lined all 4 walls and the top of his tent with t5s and i was a good grow but. he also ended up not saving any money cause insted of his normal 3 light setup he had 9 t5s so.... really its up to you. can you do it? yes. will you yeild as much? dont think so. but my patients can never tell the difference only i the grower can so give it a try you wont know for yourself till you run them. just remember they do kick of heat in a tent and when you start packing 3 4 footers in a small tent i would recomend at least a 6 inch inline(not the little in duct) im talking the ones you use to cool hoods. hope this helps