Get a J-Custom, much better guitars than Caparison (in my opinion in every single way).
But good luck with what eve you get!
I definitely agree, its more just down to the neck size really. Ikebe were kind enough to send pics of the neck from the 7570Z but it doesn't really look like much of a U shape, from the pics its hard to tell though.
The issue is its such a massive outlay without being able to try it out, would suck to go through the import process only to not like the guitar.
i'd go with J custom. I am guilty of making the same mistake of going with more expensive guitars to realize I still like Ibanez more (wiz ii)
Its just a pity that ALL the current Ibanez RG line have the wider necks now, the earlier ones that were around 56mm instead of 58mm feel perfect to me.
I'd also look at Ishibashi gakki's English webpage. You can find some stuff here that is Japan market only and if it's used, it can be shipped overseas. They sometimes get some nice J customs and some nice older Ibanezes as well.
I'm inclined not to deal with them, nothing personal but from previous experience they got super paranoid about me ordering something awhile ago, I understand their not meant to sell certain things overseas but it was a bit over the top.
And I would rather not buy second hand tbh, if local that's a different story, can at least check it out in person.