After what feels like far too long, I've now wrapped this barbarian project I've been tinkering with for the last few months on and off.
Despite initially slow progress, discovering a new handpainted texture workflow in Substance Painter and a new piece of rigging software has shortened things down immensely, potentially upwards of 2-3 *weeks* of real hands on time and I'm super happy with the results.
As I'm now comfortable building textures tactically and procedurally in Substance with only some minor Photoshop cleanup, I was able to get the bulk of the colouring done in only 2 days, down from my usual estimate of a week.
AccuRIG was also crucial in getting the character rigged and posed in good time, with minimal fixes and reskinning needed after the initial pass (namely around the hands). Being familiar with Max's skinning tools already certainly helps, but as a tool to add to my arsenal for free, you can't really go wrong with it.
Inital highpoly sits at 5.36 million quads and was baked down to an animatable 13,915k quads, well within my budget of 15k I'd set prior to starting.