I got a BTB 675 as 5 string, neck isnt alot bigger then my old 4 str.
I use my B to play stuff on my E aswell, since playing 1 string fast is easier.
http://www.youtube.com/watch?v=47nnpYyY2og
here is a guy with 5 string playing alot on the B string 7, when the original of this song was played with 4 string, thus preventing alot of moving around and such.
To get the feel of an extra string just play scales or the
--------------
--------------
-----------3456
------2345-----
-1234---------
etc.
thing up and down. This is a nice finger excercise too.
Also name the note you're playing
I do play in a band which uses alot of B notes that's why I got my 5'er.
Play (dunno if you're a metal fan but) Inis Mona by Eluveitie, Gallery of Suicide by Cannibal Corpse, and Mineral by Atheist (just make the stuff on the e on 7 b)
Stuff that utilise all your strings is best imo.
This is what got me close with my 5'er. Also do some funk, cuz its cool. (slides are awesome :P)
Anyway, good luck with your extra string!
You can do it!
hope my yabberdapper makes sense