One quick tip that made all the diference for me, when you scrape it, make sure you use pulling motion with 45deg angle instead of pushing. That way you wont pull any of the wax out of the base.
I'll have to disagree. You want to remove as much wax as possible. From my understanding, wax is absorbed into the base, anything that can be removed with a scraper does not at all affect the wax absorbed into the base. You want to remove ALL of the wax your scraper can possible remove - all of course without gauging the base.
I can't remember who says this on here, but "Scrape, and keep scraping. Then when you're done, scrape some more". To the OP, your first few times will seem daunting, but grab a beer or a joint, and get into it. You'll get much faster and efficient over time.
If anything I've said is wrong, anyone, please correct me. As I mentioned above, my technique has worked amazingly for me compared to friends and shops. So I'm pretty confident in it, but doesn't mean that there isn't a better way.