NewlyVapeLover

Well, dang. Try rinsing the coil under very hot water, soak it until the water turns cool and then let dry overnight. That should help better than nothing.

I mix my own juice and the only difference basically is the flavor and have noticed that some gunk it up more than others. When I use a flavor that gunk's up the coil fast I add a few drops of water to it and it seems to help some. 

"Each time" Tam is referring to is each time you change coils, or change to a different juice.  Lower resistance coils like 1.5 or 1.8 will require a little more power (Wattage) than the 2.2 Ohm coil you're using now.  The one you're using now is a cooler coil... it takes a little longer to heat up, but is good for long draws because it heats slower.  If you want a little more heat, you may want to try a 1.8 Ohm coil... most of us prefer those in the KPT2.  Also, adding a Kanger air-flow-control base to your tank will give you more air-flow and is adjustable to make the vape more personalized.  The bases can be found online or at most shops for $3-7, and make your KPT2 that much better!
Welcome to Vapor Talk!

You set either the volts OR watts, you go with one at a time, not both at the same time -- if that makes any sense. So, if you're in wattage mode, set that. Leave it at that.
As for the "highest" you should go in watts or volts, start low and vape. If that doesn't do it for you, turn it up a little. Vape. Keep repeating that until you get a slight burnt taste or a harsh vape. Turn it down just a bit and that will be the sweet spot for that tank-coil-juice combination. Each one will be a little different so you'll just adjust each time. I've noticed that fruit flavors like lower heat while bakery flavors/coffee flavors like it hotter.