Regarding reference points, yes the tell tails. I also have markings on the vang line to aid repeatability. I also use a wind vane at boom level, used purely for when running. It doesn't necessarily tell you the wind direction, but you become familiar with its movement ie. when it goes round in circles, i can go a few degrees deeper but no lower since its slow. Keep in mind sailing low has its place, but faster can be sailing higher angles depending on wave state.
Nigel 5780