Normal nut spacing is 45mm for a 5, 47mm for broadspaced. I've got one of each on the wall
Spacing at the bridge is definitely 20mm for broadspaced, however with the side to side adjusment I can get my Jazzman from 16.5 to 18.5mm.
One factor I have always liked about Warwicks is the adjustability - nut, bridge, no screws on the truss or electrics cavities.
Broadspacing is standard on the Stage One 5 and 6 only - you can specify it on the LX5 and LX6, any other model would be a custom shop order.
I'm also starting to be convinced that the reasons why Warwick B's are so tight feeling and sounding are 1) angled back headstock and tailpiece much lower than the bridge and 2) wenge boards.
All 3 of mine have different neck woods, body woods an electronics, yet they all have that same punch at the bottom end.