Wow. So not much wintergreen at all?
Do you find that the wintergreen dissolves in the water? Maybe it was the type of wintergreen I used, but I found that it seemed to not dissolve, that I could see oil bubbles in the water when I stirred. The wintergreen seemed to go to the bottom unless I stirred. That is primarily why I got the xylene, also since so many people seemed to be using that. Then the wintergreen seemed to form a solution with the xylene, no bubbles. It worked well for me, but as you pointed out, I'd rather not be heating xylene.
Your method sounds great and relatively quick. Mark's method also works, but takes more time.