Not much point in building a tent or walls as no one can see in the building anyway. You could surround plants with panda, turning the white toward the plants, but I doubt if the reflected light would be very strong. It's a good idea but I doubt if the expense is going to be very beneficial because you'd have to make the tent pretty large to accommodate that many plants. I think it would be a waste of money, but that's just my opinion. Krusty grew large plants in a small warehouse without panda and it was successful. A bathroom would be too small for 5 to 10 plants, especially if you really want to let them grow. Just hang bare bulb lights from a frame and spin the pots around once in a while to expose the other side to the light should be fine. Hang sodium bulbs in the middle and put flouros on the outside, standing vertically if you can make that work. Build a small frame to support them so they don't fall over. Takes a little effort but can be done.