I have an old 36x36 soft box from Larson that I have never used. It was gifted to me. Its in good shape, but the white fabric seems a little discolored and Im not sure of the reflective ability of the silver lining. In fact Im not sure what kind of speed ring to buy for my intended AB purchase. I am about to jump into the arena of baby/child portraiture. I have read that getting the box low is important since the kids are on the floor and that the larger the box the better, but do would you recommend a big box for kids? What size would you recommend? Should you match the size of box to your subject? If I need to buy a box how to I chose a good one? What features or construction methods should I look for? Thanks for your responses.