David Barnett
I wouldn't have any idea how a "Synthetic Based Metal Conditioner" would relate to diamond sharpening films. Camellia oil is fine, as Derek points out, can be found in some home shops, and easily ordered from nearly any online woodworking supplier. Try whatever lubricant you have handy and see if that works for you. If you go through the film sheets too quickly, and you're sure you're not using a heavy hand, then perhaps try something else.