I've heard it's best to leave a laqcuer finish cure for about 1-2 months. You probably want to get to the sanding sooner, but if you do, a couple weeks after you've wetsanded and buffed your finish it might get uneven or worse, crack.
Aparently Gibson lets it cure up to 6 months. But they're Gibson so...
So I'd recommend you let it cure for at least a month or two.
I got a book that's all about painting guitar with laquer spraypaint. It's a good buy and if you're thinking of getting into painting guitars with laqcuer it's a really good read. Here's the link : http://www.paintyourownguitar.com/
It's about 30 bucks but it's well worth it. And It has some of the best customer service I've ever had.
Hope I've been some help,
Good Luck!