I think I found a counterexample to the common wisdom that more walls always create a stronger part.
The pictured S shape is 1.5mm thick, so printing with 2 walls leaves no room for infill. My testing wasn’t very rigorous, but it seems that the hybrid structure of walls + rectilinear infill is 10-20% more rigid than walls alone. The infill adds strength by cris-crossing between adjacent layers.
I think it’s fine to include a concentric top/bottom layer, but multiple identical layers weaken the part. I also tried 0 walls (infill only) and that was garbage.
Lock some calipers (with a rod sticking out) to 1.5mm shorter than the part height, compress it down onto a kitchen scale until the rod is just touching the platform, and record the weight.
That’s just the first procedure that came to mind. I will try to think of a way to do a hook strength test today.