I know the allure of the narrow space and lower cost of a 26" box. In my last garage, I had about a 30 inch wide space just to the side of the door, before my cabinets started. I went to Menards, and tried to decide between the 41" boxes and the 26". For the 41", I would have to remove 3 feet of pallet rack shelf, and then I'd have extra space. The 26" fit the narrow space available. The clincher for me was that for about $100 less than the 41" set, I could get 3 pieces of 26", and end up with 16 drawers. I bought the 26".
MISTAKE! The 26" is a pain to use. It is too tall (I'm short, at 5'6"). Nearly impossible to use the top till, and the two top drawers are hard to see into. The narrow drawers also require you to split up your sockets, and long wrenches won't fit. After a couple of years of making do with that box, I went down and bought a 41" top and bottom box. Much better height and the drawer configuration works a lot better.
I've since added a Snap-on KRL 54" box. It's drawers are about 8 inches deeper, in addition to being wider. That is incredibly better, but it takes up a lot of floor space.
The 26" box is adequate for a good working set of tools. You won't be able to assemble the impressive, perfectly arranged and polished display cases that have favor on GJ, but if you are just a user and not obsessive about presentation, they will do a great job. They won't hold a large excess of tools or a wide range if you have a lot of specialty stuff. But, they will do a good job of holding and organizing a good working set.
The 41" box will do the same, but will be a lot easier to use and organize. It all depends on whether the extra foot and a half of space is worth it to you.
If I thought I would go to a side locker later in addition to the 26", I would just get the 41" now instead.