Mmmm, Craig not having a go at Jason, I know the razor saw will produce a thinner cut than a Dremel cut off wheel, thats not really what I was getting at, more about a neat straight cut of equi-thickness all along. Incidentally you can get diamond tipped wheels which are the same thickness as a razor saw blade if the truth be known - just not easy to use! A razor saw blade looses its sharpness very quickly when using it on composites so where there is carbon reinforcement you can go through a fair few trying to cut the slot. The junior hack saw blades are cheap and the 'cutting' tip renewable with a quick grind off.
Doc cheers for the update on the cast saws, had no idea how they worked and guess following your explanation totally unsuitable for our purpose.

marcs