OK, time for a long overdue update…
I can report that the Fiebings black leather dye is blacker than a black hole and I would recommend it over other brands that I've tested, which all had some degree of show-through resulting in a dark brown colour
A couple of coats was all that it needed, even one coat was very black, with no show-through
Once dry it showed up my poor sanding – lots of tiny scratches across the grain etc – I've sanded it now from 300 through to 1200 and arrived at this driftwood appearance – it's quite appealing and now I've got used to it, but will almost certainly go again with the black, possibly grain-filling with pewter rub'n'buff.
One thing about the driftwood look that I like is that when I inevitably smack it on the edge of a drum kit I won't be too bothered as the ding won't show in the same way as on a pristine black finish.
The Haussel pickups are looking the part – single coil at the neck – a mini-switch will be fitted to allow a few pickup blend options.