The boxes stacked sideways are two deep and the longways one, so there are five boxes per row and six total rows. Most of this stuff is books, but lighter boxes can be stacked on the second rank of the bottom and middle shelves. The top deck will be where we put oversize or odd-sized stuff.
Later in the afternoon, Lisa broke down another shelf from the garage and we took it and more boxes to the locker. There was a bit of confusion when reassembling the shelf when it turned out that we'd left a few pieces behind at the house, but as it's such a short trip, we were still able to run back home, get the missing pieces, and complete the assembly of shelf #2 just before they closed at 5 PM. They asked if we were going to need access on Sunday (when they are normally closed, but you can make special arrangements) and we told them no; we'll continue the shelf-making and box-moving on Monday.
There's enough room for two shelves across the back of the locker and two along the sides, and we will probably put a pallet in the middle of the locker for a center stack. After that is done, we will have cleared enough space from the garage to go buy the heavier-duty racks and install them in the garage where these lighter-weight ones previously stood.