OK I have decided to go with the replacing the side panels approach.. If you watch GCN or are British, that is a "hack" approach and my bolting on of carbon was a "bodge". If the strength is not enough I can always add another layer to the fork part with bolts and/or epoxy.
My main question now is what kind of metal to use. In looking it up, without paying nose bleed for titanium it seems like it is aluminum. Then the question is 5052 vs 6061 vs 7075. I was thinking 7075?? It is much stiffer according to some webpage I found, the yield strength is 572MPa whereas 6061 is 276 and 5052 is 193. The cost of a sheet of 7075 is ~2x the others but is not going to break the bank.. I already spent $200 on four carbon wheels. Another thing is the current side panels appear to be a different alloy than the main aluminum body, so I think they are already using something stiffer there. Note the current side panels are 4.15mm thick which is .163"; if I got 3/16" that would be .1875" which is a bit thicker for a bit more durability as well.
I know almost nothing about all of these stiffness etc numbers (which I got from
here and
here) so would appreciate any feedback.