Greg Roddy, welcome to the Wicked Edge Forum.
I have never seen or sharpened a pasta knife. My guess for it, based on a bit of sharpening experience and some cooking experience is, it’s not intended to be a very sharp knife. It’s made to press down through cut and not for slicing. I’m guessing a straight flat level obtuse angle knife edge is desired. You want an edge that makes long straight cuts by pressing flat and straight down with out any rocking of the edge or slicing. I’m guessing it’s for cutting folded sheets of thinned pasta into long ribbon noodles, like spaghetti and fettuccine.
I’d clamp this pasta knife centered in your vise, tip to heel with the edge totally horizontal. I’m guessing a 20 degree per side bevel angle is as narrow as you’d ever need. A totally flat level cutting edge is the goal. I’m sure it’s meant mostly for push cutting. I don’t thing you need an hair splitting sharp or a toothy edge.