Hey Josh, and welcome to the forums.
I wish we could have gotten to you before you bought a grinding jig.
Many of us have been down that road in the past and decided that freehanding was the way to go.
Several years ago I bought what is probably the same one you are talking about. I even shelled out the extra "jack" for the optional elevator attachment. After using it once or twice it was put away to gather dust. A costly lesson for sure. I finally sold it awhile back to a fellow who only has the use of one hand.
I know this isn't what you want to hear. Maybe someone around her is still using one and can give you some tips. Anyway, once again, welcome to the forums.