I was sanding out a run on a fender extension and hit primer.

Correct me if I'm wrong but need imput.

Re clear the panel, scuff, then base and clear
Or
Spray base and clear.

My base is a reduced 1:1 mix

As I read this, I suppose you could spray a coat of clear then sand and recoat with your base and clear. or spot prime the sand through and go to base and clear. basically your using the clear as a primer or really a sealer. what your trying to prevent is when you spray base over fresh clear that has a broken edge it will want to wrinkle or lift the edge a little making for an ugly repair. just about anything you can do to prevent this is good.
Jay D.