410 gauge shell box

I have several Plano Ammunition cans that I use for general Ammunition storage. The Plano PLA1212P is inexpensive and functional, but, only good for 12g.
https://www.academy.com/p/plano-1212-field-ammo-box?sku=black

I started storing 2 boxes of 12 g (25 shells each) and 2 boxes of .410g shells and couldn't put more because the .410 boxes wouldn't stack, or fit side by side. The answer was to design an insert for the Plano box that would allow me to put more shells in the same space. Now I can put around 75 .410g shotgun shells in the same space I could only put 25.