[John 550]

I would add Frame design (safety)to your list of things to check .
This is what steered me toward ERA . The frame has pre
determined points to give in the event of an impact , starting
from the front : one tube inside the other with a sheer bolt just
behind the bumper , the fram will fold at the joints etc.
I did not feel comfort in the 60's design (two round pipes)
Just a thought