I understand that Vai's preferences may have changed, but to me, there is a huge difference between these necks. It's not so much as the width at the nut, it's the overall thickness that bothers me. Maybe it's the actual shape of the backside, C D or U. I may be getting "profile" confused with shape. Both my DNA and 90 HAM are thin necks as with a DBK. My VWH feels a lot thicker than the three of those. My DY is a 1987 and is even thicker than all the previously mentioned guitars, which I knew when I bought it. ( I only bought the DY because I wanted to try a maple necked Jem.) My UV77MC is a completely different animal, so it's not being considered in this comparision.
As far as the Jems are concerned, I'm getting fed up with this particular inconsistency. These guitars cost a lot of money, as most of us already know. But, I can go and buy a bunch of RG570's for $600 each and have a consistent feel. Of course, I'll lose the quality, sound, and features of the Jems. I'm just confused and extremely aggravated.
I do however, like the difference in tonal quality between these particular guitars. The PAF's in the DY sound great, as well as the Breeds in my DNA. My favs are the Evo's in the 90th and VWH, along with the ebony fretboards.