MakerBot Print is our newest print-prepration software, which supports native CAD files and STL assemblies,
allows you to interact with all your printers via the Cloud, and many other exciting new features.
Hi, the complete belt version is well documented at https://www.thingiverse.com/thing:2254103; from there you can take all items but X and Y axes, obviously, wich are explained in this project.
About dimensioning IMO those 450mm lengths are too much without adding a10mm rod alignment to X and Y; that way you can be assured against lead screws flextion due to that length.
Furthermore all you've to do is lengthening all related profiles at your will.