Looking for some advice...

I'm not ashamed to admit I know little, or rather, have very fragmentary knowledge of the build-up, or the geometrical make-up of frames and so on... and probably am a little more comfortable with riding than I am talking about riding.

Given this^. I would suggest getting an OTP (see Ga2G's thread for all your options) to start with.

a) you will likely have a flip-flop hub to try fixed or SS if more comfortable.

b) stuff will break or wear out (or you will fancy a change) over time and you can build up your mech knowledge and tool collection gradually.
Depending on your energy, inclination and cash money, you will sooner or later have plenty of spare parts and will know pretty much how to build yourself a bike.