sebo,

What you say is true, but you are ignoring the stress riser at the edge of the rectangular stock. This will contribute to fatigue in the base material at the edge. Triangle stock having a bit of flexibility at that edge will not cause such a concentration of stresses.

In the end we are not talking about much weight, or failure potential. I doubt anyone has recorded a failure caused by either installation.

Do what you like either way.

Bedford