I've remixed this tray so it fits in the back of your Macintosh SE/30 if that's unused. This way you can access the SD card easily without having to open the case.
The fit is very snug, and you can screw the board in place with a single screw like the original. Use two similar screws to fix it to the tray bracket.
I've printed mine in some “beautiful” no-name orange PETG on my Bambu X1C with the following settings:
Original design by Alan Williams.
The author remixed this model.
I've attached it to a plate you can screw in the back of your Macintosh SE or SE/30.