I’ve got a Skjold Drakkar 6-string fretless. Pete Skjold used Luminlay for the fret markers and side dots. It’s an amazing tool to have onstage. And a very amazing bass! Pete may be able to give you some input.
For the MK models, it's an Underhill filter-based preamp (think Alembic Signature preamp) with their own design multi-coil pickups, again made by Aaron Armstong.
Update from Mark Jones. The pickups are custom-made to his specifications by Aaron Armstrong. The pre-amp on the SM models is from Glockenlang in Germany. The bridge he makes himself.
Balance and weight are great. Roughly 10 lbs. Not the lightest bass I own, but I have no problem playing a 3 hour (plus) gig with this strapped across my shoulder. As mentioned elsewhere, there is ZERO neck dive!
ZERO neck dive! In fact, Mark sent me a picture of this bass on a strap around his neck before he shipped it. I hadn't even thought about neck dive until he brought it up. Not an issue!