Here is the source of it, so you can edit it easily (Onshape is free with some minimal restriction and really powerfull. You just need to sign first if you want to open the document).
Warning, it’s for the International Version and I’m printing with a 0.4 nose with Cura (=without the XY compensation of Slic3r), so I put for example 25.5mm of diameter for the tube of 25mm.
You can edit it easily with Onshape, it’s really easy to understand. After you’ve done the edit, you can export the .dxf for milling (right click on a ‘sketch’ on the left column) and you can export the 3D parts the same way (.stl or solidworks or a lot of others, if you prefer to work directly with your CAD software) -> left bottom column.
I made it for an 11cm high in total, for my feet (with an angle of 45°), adapt to your size, too.