The J or 0000 body is physically larger than the OM or 000 models. I guess you knew that and that's why you want to change to the smaller sized guitar. Frankly, what you're proposing is so bizarre, that I can't imagine a luthier undertaking it. It would mean completely dismantling the instrument, separating every piece of wood - top, back, sides, neck, braces, every piece. Then cutting everything down and reassembling it all.
It would be far easier, faster, cheaper, to build a new guitar from scratch. Starting with fresh wood would be much easier than recycling the wood in the 0000.
-Raf
__________________
-Raf
|