Josh,
I admire your do-it-yourself style. I feel that way sometimes, but I am getting old enough that I am also OK with farming out to a sand blaster. Another consideration is how you like the significantly different looks you get from the two processes. Sand blasting almost always comes out with a uniform look. The cast aluminum takes on a bit of a dull grayer look, vs. the shiny aluminum that a grinder/cup brush gives. The wire brush look can give different reflections depending on your viewing angle. You also have to do - as I believe you do - and go the extra 2 or more miles to get to some tight spaces or still have a few black carbon stains remaining.
Either way, you are going to get a grill WAY NICER than any of typical postings of used grills - even ones where the seller claims to have cleaned them well.