I believe that one can obtain used Proxars fairly inexpensively from ebay if you are going to NOT be buying additional lenses this may be a very viable choice. I remember a Leitz advertisement from the 70's that showed comparison photos taken with a 90mm lens with an extension tube and the same photo taken with an Elpro. The Elpro was very visibly the winner. I have no personal experience in using Proxars. I am not stating that Proxars are of a quality comparable to an Elpro...of course, I am not stating the contrary either. Certainly, the Proxars do not requrire exposure compensation and are minimal as far as weight and volume are concerned.
The foregoing having been said, I have never owned a piece of Hasselblad or Zeiss gear in which I was disappointed from a performance standpoint...cost standpoint most certainly.
Enjoy your Hasselblad.