Our 32-year-old boat has all copper fuel lines, very neat, out-of-the-way original installation and they all seem very sound. I’ve read that fluid turbulence in tight bends can wear thin-wall copper out but have never experienced this. The tubing is mounted with copper straps, usually two screws on each, but I see no reason your SS hangers wouldn’t work.
The only drawback, IMO, is when it’s time to rearrange things. You have to cut, bend and—in my case—flare anew everything you change. I plan to leave the fuel supply/return lines and manifolds as they are, but when I redo our fuel transfer/“polishing” system, I’m thinking about going with hose with professionally swaged flare fittings for ease of installation.
I’ll be watching this thread for all ideas. So thanks for bringing this up.