Stuart,
There often is confusion when writing about landing gear shims. This is because the straight 170 and the 170A IPC show two sets of shims and the 170B has three different sets of landing gear shims. The earlier models have shims at each end of the gear. P/n 0541105, to adjust the height of the wingtip, is placed under the inboard end of the gear leg. Between the gear leg and the axle shims are added to adjust the camber and castor of the wheels. The 170B IPC shows an additional set of shims placed above the wedges on the outboard gear support.
Here Mark writes that the inboard shim is ".065 X 1.00 X 1.25 aluminum sheet stock with a .500 hole in the center."

- Inboard shim p/n 0541105
One couldn't find an easier part to fabricate as an owner-produced part but if you've got more money than time it's available
here.Google "0441115" or, for the same part used on the L-19, "0641115", and you will find numerous examples of new and used landing gear wedges.

- Wedge p/n 0441115 or p/n 0641116
KRN usually has reasonable prices. The 170B uses this same wedge along with shims. These shims are available new from
F. Atlee Dodge.