My first attempt at an insert - its taken me quite a few iterations and measuring and re-measuring but I got there in the end!

This is definitely a release candidate rather than final version. I just wanted to get this up there.

Made with tinkercad, will be migrating to fusion 360 when I get some time to figure it all out - but its basic and definitely could do with improvements.

Zero box lift and I'm happy with the way things slot together.

Tiles could do with a thumb hole to get them out, or you could just flip the box to create piles - we'll see how it goes with an actual playthrough.