No - I'm using Pirastro Flexocor strings - I think these have more steel, so would work better with magnetic pickups.
However - my NSCR5 only has piezos - no magnetic pickups at all. So, I tried various option and decided that the magnetic pickups contributed to the "big fretless bass guiitar sound" - whereas the piezos sounded more like Double Bass.
As I have bass guitars, I thought it best to buy the piezo-only model - it looks neater to me as well and more like a piece of sculpture!!

So people like the way that it looks and are surprised at how it makes any sound!!
B string - hmmm - not as important as on BG I think? So - on BG I use the B string a lot - but mostly to get a sound more like DB or the Amepg Baby Bass sound you mention - bassier, thuddier, more rounded tone etc.
But on the NSCR5 EUB, I find the tone is already like that - so I don't need to resort to the B string. In fact it can get in the way.
But it is an awesome sound - incredibly bassy - and it is nice to play a low D or C just occasionally - say as the very last note in a piece. I have got some nice reactions - as in, what was that!!!
Especially when playing the low D below the bottom E, for some reason it seems to resonate through people !!
