Alright, I'm tearing my hair out over this question. Any help would be appreciated.
A Scuttleboss has The Black Fang (the model's Spider Venom does 1 + d3 MWs) and the Monstrous Mount trait (Spider Venom does double MWs). He gets buffed further with the Venom of the Spider God spell (Spider Venom does double MWs).
The Designers' Commentary says that in this scenario, the number of MWs inflicted by Spider Venom are doubled twice, not once. So, let's say that you activate Spider Venom and do a base 3 MWs (1 from the model and you get 2 MWs from the d3 roll). Taking all the above into account, do you wind up doing 9 MWs (3 + 3 + 3), or 12 MWs (3 doubled to 6, doubled again to 12)? Many thanks!