I don't like the rack that much at this point but it was the one I could get to fit (Blackburn MtnRack).
I don't think I'd worry too much about the rack. I had a pair of these Blackburn racks that look like they could be similar to the one you have. They originally attached to the rear brake bolt (on side pull brakes) with a single strut. I modified this one by welding the plates on each side of the center attachment point. This allowed me to use 2 struts and attach it to my mountain bike's seat stays. My daughter is still using the unmodified one on her road bike, and the one in the photo went with my mtn bike when I sold it. They were 30-35 years old, and had been used a lot. C&V-- That bike was a 1993 Trek 820 that I bought brand new still in the original box in 2009!
OT- but again I thought you might appreciate an "old" bike.
