All things being equal, has anyone noticed SC being not as strong as HM on SS guitars? Such as more relief at string up?

I've only used it for a soprano Uke and it was plenty robust! LOL

I use Spanish Cedar but mainly build classicals. The option of adding the extra carbon fiber rods that Pete mentioned at the start should eliminate any concerns, I would think. SC is a dream to carve compared to almost anything else, and I'd try to keep using it even if my building drifted to SS.

I don't think anybody dislikes the smell, it's the taste that's terrible!

As with all woods, cedro varies a lot in density and stiffness. Some of the denser stuff can be as hard and stiff as a lot of Honduras mahogany. The lighter stuff is more like balsa.

There are lots of alternatives. I am going more with domestics these days, and find that butternut makes a decent substitute for cedro. It does tend to be stringy, so it's a little harder to carve, but not much. Some of the lighter samples of walnut can be a pleasure to carve, and compare well with medium cedro. Cherry is a good substitute in general for mahogany. Soft maple works well, and if you get curly wood and laminate two book matched pieces down the center line it's pretty showy.