T5s have to be so close to the plant that I think the benefits of the T5 side lighting would be minimal. I personally prefer to grow fewer larger plants rather than a bunch of smaller ones. I flower in a space that is just under 20 sq ft and never like to get more than 8 plants in it.
Two 600W are going to leave you underlit for your space. For 48 sq ft, you are going to need 3 600W to give you 5000 lumens per sq ft. You will need to wall off the section you plan on using or the light will disburse throughout your entire space and give you less lumens yet. Have you got ventilation set up? It is almost as important as your lighting.