Thanks guys. Yeah I am thinking 35 is the right size, it’s just tough deciding when you can’t compare. iamgps does a good comparison video on YouTube, but compares the K35 to B40, which I’m not sure is very comparable as the Birkin is bigger anyway. Thanks for your help.
I disagree, the 35 is going to end up looking like a barbie's purse on you with your built. (nothing wrong with Barbie's purses

Im 176cm and 70kg. B40 was ideal.