I'm 5'7", 140 lbs with broad shoulders and back, and I recently bought a medium PI long sleeved jersey that fits me fine. As a I recall, I tried on another PI jersey at the same time that was a "race cut," and although it fit it was too snug to be flattering.

In Shebeest, I'm anywhere from small to large depending on the jersey. I can't wear Sugoi jerseys because I'm between sizes with everything I try on, except I got one of their tri tops last year on sale in large, which fits great.

So for me cycling clothing is like regular clothing. Start with your best guess at your size and expect it to not fit.

p.s. I don't find women's shorts to be too short. I wear Shebeest century or SSS shorts and they're fine at mid-thigh length.