Re: wizard neck vs. J custom neck thickness
I'll be honest with you. I have not digged into the details of every Ibanez neck, so my comment is purely based on experience. Hope it helps nevertheless.
I mostly play Sabers. Love their super thin "Wizard" neck, you can fly on those. My S1520 and the JC S3040 both have that. My S2120x has got, on the other hand, an "Ultra" neck. Kind of unknown to me why they decided to do that if almost 100% of the other Sabers released at about the same years had Wizards. The Ultra is a bit thicker. For somebody playing Wizards for such a long time, the Ultra was a bit of an adjustment. But not too big of a deal. Just a bit of an adjustment. It is a good neck I think, but would not say it is better than the Wizard, even trying to be as unbiased as I can.
My other JC RG, has got what I think Ibanez simply calls "J-Custom" neck. It feels very very close to the Ultra. Thicker than the Wizard, that's for sure. My other reference would be the now sold RG2027x, which also had a Wizard I believe (at least it was that comfortable), and my UV777BK, whose neck also feels very close to the Wizard. Very comfortable to play as well.
So a J-Custom neck would require some adjustment period for somebody who is used to playing Wizards, as I was. But I think it should be very minor, a non-issue I'd adventure to say. But only way to know is by trying them yourself.