I don't think I posted this photo before. The photo was taken a year ago to show any prospective inspectors or buyers that yes, indeed, I installed anti-rotation parts on the fuel lines.
It shows the anti-rotation devices that I installed on the fuel lines. Note that no safety wire is needed, and I didn't bother to drill any holes for it. Yes, if I ever need to remove the fuel pickup line I'll have to unrivet the brackets (nutplates could have been used), but I decided that was unlikely.
Putting the bracket on the nut blocked two rotational degrees of freedom at once: the nut can't unscrew, and the fuel pickup line can't rotate in its hole in the access port.
The one on the left is a bit bulkier than I like but that's what it took. Keen weight-conscious readers might observe that I could have lightened these parts, and I agree. I should have.