Abyssal Dwarfs Mega Army 2020

So… it’s now a waiting game. Picked up an Abyssal Dwarf Mega Army set for £79.99 posted from Goblingaming… i’m wondering, because i’m going to be making scenic bases (I will be casting them from resin after making the master) would be be better to seperate the 40 Blacksouls into 3 regiments of 13? I know MMC is 11 and PMC is 16… but if I need to add the extra 3 at a later date I’d atleast have thay options… I’ve also bought a Abyssal Grotesque Champion… what would be the best way to set up these units?