Need help with light setup in 4' 11"x2' 7" space.

I've been trying to decide between a 21" x21" (growzilla) reflector with a 400 MH and a 600 HPS or a 4' tube with two 600 HPS. I'm wondering if the 21x21 will produce enough spread of light cover the Secret Jardin 4'x2', this would be a much cheaper investment. I would also like to know the differences in yield and quality that anyone may know about between these two options. Also would a submersible heater work if it were not underwater (I will be using a reservoir in the future but hand watered potted plants this time) ?

The plants are some that I have had outside this summer and I believe that they will be fine with the move indoors but I would appreciate another opinion.
The reason for this switch is that I am moving within the month.

Thanks

my space is roughly the same size as your and I use a 400 hps in my flower room with just a standard reflector and get plenty of light coverage. If you cant control the heat then a cool tube would be great for that, but not going to give more light coverage than the other reflector.

Thanks for the response. My worry is that if have my lights close as possible to the plants that the edges of the 4' area will not be getting enough light (or not the max possible). This isn't a problem with you, how many plants are you packing in the space? I guess I could rotate/move the plants around to give all plants equal light? Sort of a pain in the ass. Either way with this much wattage I will be cooling with a exhaust fan.

I grow six big plants in my space and the walls a lined with mylar so the edges of my room are not only getting light from above the are also getting all the light reflected back off the mylar. I only move them around if I have to take all of them out for some reason then I may put them in a different spot, otherwise they live in one spot once they're moved into the flowering room. if anything i find the side plants have much more under growth than the center plants do to the reflecting light off the walls.

I use an a/c unit in my bedroom where both my grow rooms are located to deal with the heat, with fans the rooms also of course.

Yeah the jardin has a space blanket like material that is highly reflective as well. I wasn't speaking so much about the undergrowth but rather the colas on the plants on the sides compared with the colas of the plants that are directly under the lamp. Thanks

my two biggest colas from my last grow where the two at the farside.

Will a MH produce the same gram per watt as a HPS?