It looks as though you still have the original frame for the 8x10 back on the camera. If you can get the plywood off safely, you might be able to put a new ground glass in there and have an 8x10.
A good lens shade will take care of a lot of the flare. Avoid working in high-flare situations, and your lens probably will do nicely. A little flare can be a good thing in portraiture, softening the transitions between light and dark. That lens probably will do you well on your project. Give it a good cleaning and try it out!