UPDATE: I've redesigned my own version of this from scratch, you can find it here: https://makerworld.com/en/models/245371 

I remixed the model by simply combining the 'base' and 'top' part since I only wanted to use these parts anyway.

Keep in mind that the ‘slider’ and ‘bottom piece’ will be hard to combine with this, but I think it's possible. I also removed the mounts for the sequential shift mod to make this possible to print in this orientation.