Bob Gollihur's site has a huge amount of advice on all things upright. His product descriptions are really detailed, and he has this to say about the WAV 4 strings:
[i]The stock strings are a light gauge steel that serve as a reasonably decent hybrid sort of sound, but the instrument responds well and can handle most standard 3/4 size upright bass strings. I and others report good success with strings such as the Pirastro Obligatos, which are a popular, heavier gauge upright bass string that delivers a more traditional sound, with less sustain and more body than the stock strings. Keep in mind, however, that the tuning machines are similar to bass guitar tuners, so very heavy gauge strings (like the Eurosonics) typically cannot be accommodated. However, since the pickups are piezo-based, which sense vibration, most any 3/4 size upright bass string can be a candidate. They designed the rear control cover that allows you route the excess string around the bottom of the bass and anchor them in keyholes. [/i]
Just the info you need methinks?!
Cheers
Gareth