seat tube angle is set by your body, not by responsiveness. Paterek was just parroting some ignorant "conventional wisdom" from back in the day. I suspect he has changed that in more recent versions. If you need 180 cranks, your femur is likely long enough to drive you to a slacker seat tube angle, not a steeper one. The handling of a bike is mostly controlled by the head tube angle, fork offset, and the weight balance. The seat goes where your fit tells it to go. Obviously you can get a long setback seat post to compensate for a steep seat tube angle, but that flies in the face of any reason to build a custom frame. You really want to put the seat tube angle where it makes your saddle of choice look good on your seat post of choice. In other words, it really doesn't matter what the angle is.
BB drop of 7cm is pretty normal. I don't build fixies so I'm not sure if that is typical or not.
As far as tires go, I would look at the online version of bikeCad, there is a view that shows tire clearances. You also might try Rattlecad, but I'm not sure how that works for tire clearances.