I'm pretty well stuck on a 7.25" radius. I bought a 1965 Jazz in 1966 and played it through high school and some college before going on the road with a nightclub touring group for 3 years. We played 5-nights a week, 50-weeks a year. So in 3 years that's about 750 performances. I got real use to that 60's Slim C-shape neck with 7.25" radius.
And then in 1976 our house was burglarized and they took all of my touring gear except for one of my two Atlas mic stands. Meanwhile Fender really screwed up the necks on the Jazz Bass. They were still the same size at the nut, but they were a lot thicker. And some had a fatter C-shape, some had a fat D-shape, and the fattest neck of all was the U-shape neck. They all felt terrible in my hands. Then finally in 1985 I found the bass I play now, which is a 1982 Jazz with a white bound maple neck. Took me almost 10-years, but I found one!
Was working part-time at a music store while I was going back to college and a guy traded it in. By this time I'd tried all 100 to 150 Fender Basses the store had and they were all thicker and uncomfortable. Then I pull this white Jazz off the wall, played a few runs with it and it just felt like home...so I bought it. So I'm really stuck on the 7.25" radius, at least on a 4-string. Even the Jazz Basses with the 9.5" radius that Fender went to in the mid-80's feel off to me.
I do have a 5-string that has a neck with a 12" radius - wider to accommodate the 5-strings but thankfully it is a slim neck and not fat! I'd prefer a more curved radius though. it's a LOT flatter than my Jazz neck is but I put up with it because of the extra string.
You know the whole reason they started putting flatter necks on guitars was so you didn't choke out the string when you were bending notes. I don't really do a lot of bending of bass notes. I remember the neck on the guitar Eddie Van Halen was using for his tapping and bending of notes and it was super flat like a classical acoustic guitar neck, certainly not made for playing chords on it. The higher arch of a smaller radius relieves a lot of tension across the back of the hand when playing barre chords on a 7.25" radius. Of course, bassist don't usually go around playing barre chords, but they also don't do a lot of bending notes either, so the 12" and flatter radius necks make no sense to me for a bass. YMMV...probably will!
