Dremel insert for accessories box

I have a dremel which came with a nice accessories box. I have several collets for different bit sizes. They usually lay in the bottom of one compartment. When I need to change the collect, I have to bring one by one and examine if it is the size that I need. So, I decided to make an insert that will have some holes to put the collets vertical, so i can see the size at a glance and pick the one I need.

I made two versions of the insert. One is just a block, one rounded edge and holes in top. This is named solid. The other I did more work, to have only the borders. In case the round part needed some triming. On my first test, the wall of the holes were too thin, so I made corrections and put some reinforces. I think is an overkill. But I liked the design, it is more detailed.