Planning for a grow room

Been doing a lot of reading and now I have some questions

LED VS HPS
From what I have read the only real advantage a LED has over the HPS is the heat.
So I have made up my mind to go with a HPS. The issue I will be facing with the HPS is heat in the summer. It can get up to 100F outside during the summer. I have thought of putting a wicked rag at the intake to help reduce temp incoming into the room. Short of using AC to cool the room what options are there?

Soil medium
I'm thinking of using a hydroponic or aeroponic for flowering. I was thinking DWC since it was easy to make myself but the major downside to it seems to be water usage. It needs to be changed once a week. That will add up fast. I'm looking for something that is not have a lot wastefulness in regards of water but still gives good results. (Think I found my solution. I'm looking to make an ebby & flow without gravity feed back to a reservoir. Should the reservoir always have an air pump running in it?)

Light rollers
Are they even worth it? Yeah you can move the light closer to the plant but I have found little info on it. I have heard it adds 1-2 months to the flowering time.

I plan on building my own room. Buying a tent seems to be overpriced. Wood does not cost that much and you can buy mylar fairly cheap.

Any other tips and what not?

How big of area do you have? How big of light are you thinking? Ebb and flow works good but you still have to maintain your reservoir prob once a week. I ran my pump 24/7 but you don't have to. Never used light rollers. Again would depend on how big your going. I doubt it would add 1-2 months extra to flowering if any time at all.

have tent and room, have been bragging on tent for 2 years. this winter got zapped by P.M. tent total loss, room recovered, think it has increased air flow cooling--have frozen 1gallon milk jugs for the tent, when outside air just to hot.