I am new to raised panel doors (just got PC router and table setup). I
made a few raised panel samples and it's cool. Now I like to use a
software to calculate measurements for the pieces of wood.

I download a software, believe it's "Software for Woodworking". Since I
am new, I think I could follow the diagram and measurements. I just print
two sets (40x20 and 15x10) to try study from there.

If there's other software you experienced, could you post the link for
me?

Is it generally common practice for the (top/bottom) rail and (side)
stile set to 2 1/2" wide??

Per above statement (2 1/2" wide), until about how short (overall) width
to start using narrower rail/stile width? I am asking because I foresee a
project where I might will need to use a 5" overall width (two on each
side, permanent, not doors).

Thanks.

Chuck