I got the one wash because I hate doing the guess work on how much they'll end up shrinking and, like you mentioned, I plan on washing and drying them indiscriminately. I find they fit one size small - I'm usually a 32 (or 48) and went with a size 33. They measure 41cm across the waist. The tough thing is getting the length correct. They "standard" fit is ankle-length with a single cuff and they come in different inseam lengths. I'm about 180cm tall and took a length 32.