UHF, a word from my experience is this
1.make sure you have 24" as your INSIDE dimension, as 24" light fixtures will not fit right in a box with 24" Outside dimension.
2. Once you have lights & a filter in the box 48" seems awfully short when you have a plant that suddenly takes off on a wild growth spurt. Second box is 60" tall and does not seem so cramped. Remember the light hangs several inches from the top of the cabinet even when pulled up as high as it will go and the pot puts the plant several inches above the bottom, so when added together you have "lost" between 10-16 inches.
it isn't the best use of your sheet-goods, but I was fairly frustrated to realize my light fixture was going to be at a tilt in my 24x36x48 box if I wanted to use it in the cabinet from side to side rather than lengthwise. I would have shelled out the extra $20 had I realized before hand .
Obviously, you may have factors that limit your size selection, but if not these two things are issues you should consider.