The thing that trips people up with positionals is that they think they have to be positioned directly on the E/W sides of the target for the positional to count. As long as you're at the SW/SE side then you are at the flank, so it's literally just hit a GCD, move 1-2 steps during the downtime, hit next GCD and repeat. As for bosses spinning around etc. fights are scripted so unless you have a bad tank then it's simply a matter of knowing/anticipating when those moments are going happen and act accordingly.

Anyways if you want a job with no positionals, SAMs your closest bet since their positional bonuses are potency based IIRC.