Have fun, Wista's are great cameras to use, and you'll be amazed how many people will stop & talk to you when you use it, just remember when they ask is it old, say it's remarkable what the Japanese make now
Congratulations. You are going to get hooked on large negatives. If you haven't already, do check out the large format forum; there are some articles there that might be useful to you.
A roll film back is very useful, it means you can switch to 120 film when you're running out of film particularly when out shooting all day.. There's a Wista version that has a plate so it can sit under the focus screen if the camera doesn't have the Graflock type back.