Made this version to fit on just a single front seat. I had to make the distance from the headrest to the iPad holder larger. This version can be used both as one and two seat versions. Only difference is the length of the aluminum tubes.
Print the parts on your 3d-printer. Try to follow how I positioned the parts to ensure best rupture strength for the individual parts. Use a power drill to make the hole go through in part B.
Then get the following from your hardware store:
2x18cm 10mm Aluminum Tube (shorter than original design).
If you like, you can make another set of long tubes to place it between two seats as an option.
5 pcs M4 30mm (or preferred 25mm) bolts
5 pcs M4 nuts
2 pcs M8 60mm bolts (longer than original design)
2 pcs M8 nuts
Follow the images of the original, if you are unsure how to assemble the kit.