For that extra half degree on your ski base edge, use the 0.5 Degree Base Bevel Guide from FK SKS. This file guide requires a 10 inch flat file, and is 25mm wide.

Base beveling guide
0.5 degree bevel
Requires 10in (25cm) flat file
25mm (1in) wide

Part Number: FK SKS: 3161
UPC: 4250493730878