After inspecting the grip in meshmixer, i saw that it was actually a two-part file, so i parted them and oriented the files correctly.
The only parts that needs support, is the grip end.
The other parts need no support at all if you have a good calibratet printer.

The center tool is, as the name already says it, a tool that you put on the grip where the blade is mounted, so the blade is centerted.
Use cyanacrylat to glue them together, but take care to put only a little glue on it, so that you have no overflow on the sides, wich can or will result in the center tool glued to the grip!

If you have problems mounting the tool on the grip, just sand the area around the grip a little, i tested it and it fits tight.

Ultimaker

Ultimaker 2

No

Yes

0.15mm

30%