Reloading Tray Block Stackable Bridge for .223 .300 Ammo

I have different kinds of retail ammo loading trays, most of which are meant to be universal, and while they tend to work for most rifle loads I use, they're big and bulky and take up lots of space on the loading bench. I also found that once in awhile I lose track of where I am when I'm loading ladders and it forces me to count groups of cartridges so I know where on the ladder I am and what weight of powder I'm charging.

This was inspired by the bleacher type trays I've seen here and there because I wanted to make something somewhat compact, but also needed to make sure I could reach each casing and not risk fumbling with my fat fingers. So I came up with the following requirements.

1) Because I'm wanting to keep track of ladders by round, I want each row and column marked by coordinates (in this case LETTERS and NUMBERS)
2) Because I wanted to store these compact it needed to be small. I determined based on my ladder sizes that I could make them hold 25 rounds each but stack