Only clues 1 and 2 remain in this puzzle for me. The others are scratched out (but show here for your reference).
I've tried substitution for clues 1 and 2, but nothing on the grid can be substituted into clues 1 and 2.
I've tried to see if there are any matches within sub-squares where only two items have two spots open. Nothing.
I've tried to see if a line in one sub-square compliments a line in another square. The last one I found was row "MKP 427" compliments "43 Light Years" which meant in the top middle sub-square, I could put an X for that match-up.
The only math was taken care of already. So no notes to take and calculate.
Anyone have an idea of where to go without doing "What If?"