If you are looking for a slim tapered fit in BoO Chinos, you should size down to a 0. I have a 28 inch waist and I thought they would fit tts, so I purchased a size 0. They were a little too big for me. IMO, if you are going for a slim tapered look, don't go for BoO chinos because they are made to be a classic straight leg.
I'm not sure about this. I'm generally a 30-31 in trousers and I take a 1 in the BoO chinos and feel they fit slim and tapered, I think leg opening is about 7.25"-7.5" (max) on the 1's. I really like them personally, but all of mine were purchased on deep discount. I like the notch back detailing and button/hook and clasp closure. They're some of the slimmer yet non-constricting chinos currently in my closet. The fabric lends itself to being easily dressed up for the office or down for weekend casual wear.
^This video pretty much explain it. Got myself a school boy blazer and a varsity this year. They fit so well!
Thanks for the video, mellow. Glad you got your hands on some. I really love the tweed blazer I own. Fit perfectly for me right off the rack.