Re: NGD j.custom RG8550MZ
The tone is definitely a little "warmer" than your standard basswood body RG. I haven't played it a huge amount as work has gotten in the way, but so far it plays beautifully as you would expect and feels every bit the high-end guitar.
The thumbscrew on the left of the bridge is actually the intonation tool for the edge zero trems. You unscrew it all the way to remove it from the bridge, then screw it in to back of each saddle. With the saddle loose, you can turn the tool to pull the saddle back in a controlled manner.