DWC setup Questions

I am setting up a little garden and have a few questions I am hoping you folks at RIU can help with. I am limited to 47 inches high but am looking at a 4 foot by 3 foot box. the area this is going in is cool and tends to be at around 10 degrees Celsius or about 50 Fahrenheit. I have looked at posts and videos here but I have a few questions:

Should I insulate the box?
Cfl's or a 400watt hps ml? Going to be doing 2 plants at a time, each in a 5 gal Bucket
I am going to be away for 14 days during the grow -set the light a bit away from the plants when I leave? I was hoping to be going to 12/12 before I leave but may have to veg a little longer?

any and all advice welcome, I have 2 outdoor grows but first indoor grow and first hydro

Instead I would get a Lighthouse Hydro Blackstar 135w ...super cheap to run and can grow 2 plants.
CFL are on the weak side and 400watt hps ml is a energy sucker.

You will probably need to use the HPS light just to keep the space warm enough. Get the light and run a 24 hour cycle with a thermometer/humid meter thingie to track things. If temps are still cool, you might end up insulating with some rigid foam insulation or something. It also depends if you are going to be venting the box with a fan and/or filter. IDK about going away for 14 days, especially if the plant isn't a seedling or something at the time. I would think that most plants would deplete a 5g bucket, especially since you will only prolly have 3g worth of water in it. You might just want to start up things when you get back from that trip or w/e. The only way I could see leaving for 2 weeks is if you had one hell of an automated drip-to-waste system tied into a big res($$$), which isn't the direction you are going at this point. With the bucket height added, you arent going to have much space to go up. Do some topping and LST early on and don't go to flower too late with a stretchy strain. Good luck with whatever you decide.

Thanks for tips guys. Anyone else want to give their take on this?

I wouldnt get the blackstar for that area. You need more coverage than that one 135w can handle. Id go hps if you can, maybe a cool tubeso you can keep it high up and keep heat down. I doubt youll have any water in your buckets if you leave for 14 days....just sayin. Youll probably have to get someone to watchem. Put a screen in, top them a couple times to get enough tops to fill the screen and then flower when the screens full. Have fun