The spec is 39-46 psi at idle and 48-56 psi at WOT. I wouldn't be overly concerned about the 47 psi at idle reading.

As for an adjustable fuel pressure regulator the B&M piece is fine, just make sure you don't actually try to buy anything from Endyn. It's a good website but the "company" is little more than that Larry guy selling stuff from the garage at his house.