The original method for museum specimens, cleared, stained with 
alizarin  and mounted is:

Dawson AB. A note on the staining of the skeleton of cleared 
specimens with alizarin red S. Stain Technology;1926;1:123-124.

I am not sure when the alcian blue stage was added and have not used 
that stage.  I imagine the density of alcian blue staining can be 
gauged quite easily by eye.

If you cannot get hold of the original technique paper, it is 
certainly given in every edition of Culling.
Russ Allison, Wales