To fix the roof curve, I used four aluminum girders at $300-400, which weighed 16 lbs each, and this increased the weight enough that lifting the shell alone is a bit difficult and I am changing two torsion bars.
Wood might be lighter.
The cross members also catch bugs in transit and I am thinking of some streamlining with sheet metal.
This repair was worthwhile for me because I also wish to mount big ham radio antennas, and the aluminum works well for that. I don't know if it would be worthwhile for anyone else.
See
this thread.