Following up on Teds tip about the BT1517 and having finally taken delivery of my FX Wildcat in .25, and having acquired the required courage (beer may have been involved). I finally bit the pellet and took drill to stock (or more accurately drill and drill-stand).
The stock of the FX Wildcat seems to be made of some kind of reconstituted plastic/rubber combination. This makes for a very tactile warm to the touch stock. Whilst the down side of this material is that it doesn't hold threads very well, the up side is that it does machine well.
Below is a picture of the bits I used to attach the rail:
~original
This next picture shows the inside of the stock with the rail fitted:
~original
These next two pictures just give an overall view of the finished stock:
~original
~original
Basically drilled two 6.5mm holes perpendicular to the underside of the forend at the required spacing, then using the 6.5mm holes as a guide, counter bored the holes from the inside of the forend with the 22mm flat drill (again perpendicular to the underside of the forend). Finally using some thread lock, assembled the bits. The trick is clamping everything together solidly to hold everything in place and level while drilling, but other than that the material the stock's made out of is easy to cut into.
One FX Wildcat good to go.