Lindsay,

Have a look at the AHPC website (link below)

http://www.ahpc.com.au/pdf/Using%20Smart%20Lk%20Snap%20System.pdf

This may give you some pointers.

As to how far under check out some of the pictures from the 2006 training weekend at Hazelwood. There are some photos of ruddes similar to yours. A link is provided to phot albums from the VMCA website.

Regards,

Peter