I just grabbed this one so don't hold it against me because this is not how it looks when packed for a trip. :grin:
I also realized that I misspoke earlier. I set the slots 2" on center instead of every 1". The dividers have the "notches" on the side so that you can actually get them in and out. If they were full width all of the way up then the would hit the lip on the top of the box and you couldn't move them. The holes make them a bit easier to get in and out but are not strictly necessary. I made mine very tight so that they wouldn't move around.
The dividers aren't full height either. This allows for space to lay bigger items on top like the k-pump or sand stake. I have had them in for about 4 or 5 trips so far and the only thing I would do differently is saving the effort of making a divider for every slot. I now have 2 or 3 extras that simply aren't needed because I found that I always have a couple of bigger items that take up more than one slot, like the first aid kit in the picture. Regarding the width between the spacers, I got lucky more than anything...the wider slots wedge a handle of booze in very snugly, but if they were even 1/2" narrower then it would not work so well.