I got interested in string spacing... especially on 5's... I did a little web research as well as played the fool with a ruler in a few music stores, and while this is not at all comprehensive, this is what I found... Standard 5: 17mm Wide 5: 19mm Standard 4: 19mm Wide 4: 20-21mm Very abreviated list of examples... Standard 5's: Peavey (incl. Cirrus*), G&L, Fender, Zon Sonus, Spector... Wide 5's: MTD 535, Roscoe LG/SKB, Zon 519, F... *The Cirrus' ABM bridge comes standard as 17mm spacing, but judging by my measurements and the amount of lateral adjustment in that bridge, it's theoretically possible to push all the way out to about 18.5. The only caveat at that point would be that the outer string paths would not be as straight as stock, so it may be somewhat possible for a very aggressive player to start breaking G strings, but this is unknown/untested. ** The Rosco has a Hipshot bridge with width adjustment, but even though the lateral adjustment on these bridges is less than the Cirrus' ABM, the Roscoe is already at 19mm, so it's likely unnecessary to do much with it. Conclusions: ------------ Judging by what I've seen in most posts, most hard core slappers seem to really like the wide spacing... either by sticking with a 4 string primarily (like Victor Wooten), or by going with a Wide 5. I believe this is most likely due to modern slap styles where you play "through" the string a lot, where space between the strings may help enable this. Personally, slap expertise is not my strong point, so this is mostly via observation. Most of the primarily finger style folks seem to prefer the narrower or Standard spacing... probably for speed and comfort. For myself, I definitely feel a bit more mobile on a narrower bass, but if it gets too thin, I really don't like it. However, there are also the exceptions, such as the ultra-narrow 5, which I saw as narrow as 15mm. Also the ultra-wide 4, which I saw as a good 22mm, maybe slightly more. Also, at least on a few I thought to check it on, including the Cirrus, which I probably studied the most, it seems the spacing is kept pretty even BETWEEN STRINGS, which means the "centers" got a bit closer as you went from low to high (since the strings are smaller). If this is typical, I'd guess this is a "setup trick" to make the bass feel faster and more consistent for the particular player. I never really messed around with string spacing much, so if this is already well known, it was news to me. I started this because I thought the Cirrus I used to have was spaced the same as the Roscoe I use mostly now, but when I found out otherwise, I wondered why I never noticed. With that in mind, what I also discovered, was that, while 17mm and 19mm feel very comfy to me, going down that last mm or 2 to 16mm or less all the sudden felt very cramped. It may not seem like much in absolute terms, but it made a huge difference to me. This is probably most subjective, but that's apparently why I didn't really notice my Cirrus wasn't spaced the same as my Roscoe or MTD. They all just felt "good", which may have more to do with setup than absolute spacing. Dunno. You decide.