I have been in contact with Dave at Eternal Guitars and Pickups and he was kind enough to supply following info:
Hi Howard,
Thanks for getting in touch.
Yes, I know those pickups very well. They were originally designed to produce a bright, glassy tone and offer players with rosewood fingerboards a tone similar to a maple ‘board.
I used them for a few years, before deciding that I actually for preferred the ’Timeless’ models (which I’ve since tweaked a little to my taste) as they offer a far more authentic vintage sound to my ears.
I don’t currently have the Blackjacks on my website but I do have the winding spec. if you ever wanted another set.
All the best,
Dave