Re: Fretless fingerboard leveling
GHS makes a string called Pressure Wound, and a bunch of others make strings that are similar (D'Addario Half-Rounds, SIT Silencers, etc...). I'm a big fan of the Silencers. Smoother feel than rounds, more punch than flats.
Worrying about the wear on the board is about the same as worrying about wearing out frets. The marks on my 21 year old Warwick's board were significantly wider than the strings, and obviously the result of someone bending strings. If you play it with good left hand technique, meaning no death grips and doing vibrato/slides up and down the neck instead of across, the wear is pretty inconsequential.
All this stuff is personal preference, and I'm not saying anyone is right or wrong, but I've noticed that the same guys who say not to worry about wear are the same ones who advocate setting the action as low as possible. Makes sense to me, and the bass is stupid easy to play and sounds great that way.