Good ad. While I see no path for Paul to win, this the sort of ad he should have been using 4 years ago to get more mainstream republicans on side.
As far as latching on to Reagan, I don't really see a downside. When people look back at his presidency, most remeraber better times, a resurgent US, and the end of the cold war. Very few people remeraber the details, and the majority will ignore anyone trying to knock down that presidency. It's good politics regardless of your opinion of Reagan, because the vast majority think highly of him.