Valkenburg/Castleford style caliga step by step

[Sutoris]

Other than the color, how is this stuff different from Bee's wax, or simply pre-waxed thread?

Well, bees wax and shoemakers pitch(we call it cod) are two different things.
Bees wax is a lubricant and cod is a "glue".
1 It prevents the hemp/ flax thread to take up moist.
2 It "stick" the thread to the hog bristles
3 Pulling the threads thru the leather the cod is warmed and after cooling down
"glue" the threads together and lock the stitch.

One easy way to make a cod:
take rosin and beeswax 50/50
melt it down au bain marie CAUTION: highly flammable, very hot, and stick to your skin !!!
mix some drops of veg oil in it, if the cod turns out to be to hard you always can ad more oil later.
poor it in a bucket of cold water and make a bal of it under water, it's still hot!

this is not the real shoemakers pitch but it will do the job