I'd go for their year-round Super 100's, which (I think) are currently mostly out of stock but hopefully will get restocked as Spring/Summer comes in.
The sizes Jameson posts are accurate, so you can see waist, thigh, etc... measurements for the pants. If you're worried about the thighs fitting you might size up and take the waist in. But in my experience with HY the USA-pants are a great slim fit with a little more room in the thighs than the Italian-made (I size up in the Italian-made trousers for that reason).
Thanks for the reply. I just ordered a pair of Four Season Super 100s in dark gray. Seems to be about the most versatile fabric/color HY offers. My actual waist measurement is 35", and I sized up to 36 in these since they're the made-in-Italy variety. Looking at the measurements, I think they'll work for me.