HMAN...
I'm not the most mechnically inclined...LOL...what's the best way to do that, or am I better off bringing it in?
Fairly easy process. I simply found the center of the rear axle and marked it with a punch (both sides), then used calipers to check the distance from the inside edge of the frame. You loosen up the rear axle, loosen the set screws that hold it on location, I push the wheel forward to gain some belt slack and then pull the wheel back and eyeball the belt for straight, and then start to measure and reset. By turning the set screws on either side you can set it within .005. That is usually close enough.
You will need to raise the bike to do this, so if you have no lift, take it in.
And if the soap stopped your squeek even for a short time, chances are you have the dreaded belt squeek. Lots of threads on that one.....