I'll put in a vote for the Graftar. I bought a Century with that lens, It was equal to a Planar I later had installed by Graflex.

Also, I can't say enough good things about the SVS Prontor shutter my Graftar can in. I was routinely having to have CLAs done on the Planar, yet that Prontor never required one. Based on my experience I wouldn't make that swap. I don't think you'll get noticeable improvement with the Optar.