Atari 800XE : Designing a 800XL Multi Game Cartridge

I've had an Atari 800XE in my collection for a long time, picked up at some thrift store a few years ago.
Bought this bare Atari 8 bit machine without anything, so built a power supply, made a video cable.
And then we could start testing, to my great surprise the machine works and so I wanted to see if it also wanted to load something.
Created USB to SIO cable, configured virtual machine with Aspeqt (image server / virtual floppy drive).
but that's a bit cumbersome, so testing more than once has never happened.

So I decided to design an 800XL Multi Game Cartridge for the Atari 800XE

(it should work on the 800XL too, but I don't have one to test it with)
I quickly found a blueprint of the board dimensions, which I used to draw an (approximately) equal model.
The electronics in it were no problem, the port of the Atari 800 is well described.
I opted for a first simple variant of the PCB that, as a 800XL Multi Game Cartridge, can switch a maximum of 4 x 16 KB in a 27C512 Eprom

Continuing on my hopeful success I already have a 800XL Multi Game Cartridge XXL as a design, but first let's have this PCB made to see if it fits (and works 🙂 )
In the meantime I have already had a number of designs printed that did not work well in practice, did not fit well, or that turned out not to be workable 🙂
But one learns by doing and when I see where I am now compared to a year ago I think I will be busy for a while before I get there i want to be... or something