I agree the baking pan is a total waste of time and product. I'm an advocate of testing the exact product you will be making/selling in the exact same proportions; i.e., if you're going to end up with an 8 oz mason poured to 6 ounces, that's what you should test. Too much FO can cause the wick to fizzle. It can also create pockets of oil or weeping within the wax. 7% certainly shouldn't do that, though. In fact, the difference in 6% and 7% should be minimal. It's when you get close to the maximum FO the wax will hold (or more) that you run into real trouble. If you're seeing a smaller mp with higher FO load, just increase the wick size and see if that takes care of it. You might have to switch back and forth between not just wick sizes but wick types, too. For example, if an HTP 52 doesn't give you what you want, try a CD 6.