Are they suitable for wearing under baggies
Might sound odd, but why wouldn’t they be? I’ve personally never had baggies that aren’t any good under though thicker ones get saved for colder weather. (though due to them turning reasonably see through when (s)wet I’ve had some that are very much not good for wearing without).
My limited experience of Rivello sizing is its about where I’d expect non Italian sizing to be, putting me in a medium to large, not especially long unfortunately though meaning I’m into xl or xxl for things that don’t stretch.