Your prayers have been answered.
I have spent
decades experimenting and looking for resources to organize trucks. About 10 years ago I came upon a really good bin resource.
Global Equipment Company Inc
This is the style of bin. You can get dividers and put them into slots every 2 inches. (Use PVC gray glue to help hold them in place.)
Search around the website for the different sizes available. They come in 12" and 18" depths. Ideally you build your shelving to fit the bins so you can maximize space. I went with the 18" deep bins and most of them are the narrow ones. I included a few larger ones for some big items but 95% of typical electrical stock fits perfectly into the 5" wide bins.
If you build the shelving to fit the bins you can really cram a lot of stuff in.
I have had some of these in service for over 10 years and haven't broken a single bin.
I would seriously consider finding a way to extend your shelves to accomdate the 18" deep bins. You will get 50% more storage space.
Edit: Fixed link