Actually, I think the streamlined fairing is better than that, though it depends on the exact shape and the Reynolds number. On a Breezy, although it's hardly worth it, a bit of thick tape that makes a small bump (.01") placed on either side might lower drag on thick struts. (And on round ones too.) I don't know the exact best location. Prevents separation. I wonder if you went around and placed such tape on ALL the round tubes on a Breezy if it would make much difference?
As far as the structures go, I have no idea why I did it, but I figured out the moments of inertia, and now I have a little spread sheet to do it with. I approximated the struts by hollow ellipses. In real life their moments of inertia are probably significantly less, I'd guess. Anyway:
big strut long way is 0.397 and short way is 0.104
If one could find some rectangular tubing 2.5 X 1.25 with .065 wall, then the numbers would be 0.385 and 0.129
Given that the first numbers are a conservative approximation, I think the latter size would be an excellent substitute, assuming you could find some.
For the little strut, 0.082 and 0.21
A substitute, if you could find it, might be 1.5 X 0.75 tubing, .065 wall, which gives you 0.078 and 0.025
Unless I messed up my math!
If the jury struts constrain the tubing fore and aft as well as up and down, you might not need to worry about the higher number.