I always use a 45 degree prism finder. Pressing the finder against my forehead adds a great deal of stability to a hand help shot. Wilde makes this suggestion as well.
My first 500 C/M came with a flash bracket grip. It was very ergonomic, and included a cable release. I could manipulate the necessary controls with my right hand, and I really liked the 45 degree prism. You can find the flash brackets for well under $100. My "new" 500 C/M has a 45 degree prism mounted, but I'm fairly comfortable not using the bracket grip this days.
Hasselblad's are a little like cocaine: God's way of telling you that you have too much money. I have several, starting with my first, an SWC. Still my favorite camera of all time.