When I replaced strings in electric guitar from .9 to .11 I had to adjust truss rod. Classical guitar has no rod so is it safe for guitar neck to put high tension nylon strings and tune It standard?
No problems with nylon strings; just don't try steel strings on your classical!
As for high tension strings, my teacher recommended -- and I have since used -- Savarez 520R Traditional Red Card high tension strings. They have served me very well, so I never explored further alternatives. The unwound trebles have a nice texture to them, distinct from the smooth glossy finish of other brands. You'll probably find that the D-string will be the first to fail, but by then you'll be ready for a fresh set.