I don't think you'd be as lost as you think. You play(ed?) DB as well, right? I find the side markers get you most of the way there, and your ear will do the rest. I played lined fretlesses before, but on unlined I think my intonation is actually better!
The Bart electronics that Roscoe uses are really great - I love the Bart/Bart combo in my fretless. The new fretted has the Nord/Audere combo and I think it's amazing for what it does (a bit of a different flavour). I've also owned a fretted with stock pickups and an OBP-3 which was different from Bart/Bart, but very nice also. I'm glad you're digging the sounds, but don't give up on the Sadowsky - they have their own magic, at least as far as certain genres go they seem to be the perfect sound. The feel is not for me though, so I own Roscoes instead
