If you are going to drill new holes, you can use that same mast base, as you will be drilling all the way through both anyway. Clean up both the mast base and inside the mast, add some goop to seal it, insert, drill, rivet, and step it again.

Oh, and it looks like you didn't have any grease on the ball that goes into the beam (unless you cleaned it off before the photo shoot), you want to put a little bit of something like axel grease or lithium grease or something down into the ball seat so it will rotate easier with less wear. Hobie even sells some small white plastic discs you can put in there, but you can cut up an old plastic milk jug for the same effect.