The premium range does seem to be slimmer but the a design like the highway man will be slightly wider than a premium half belt.
The sheene is a similar fit to a cafe racer and slimmer than a standard bike jacket. The issue is neither Thurston nor aero provide any measurements so its all a bit vague.
As JJ said the premium range is as slim (possibly more so) than the others you mention. If it helps, Aero's sale page tells you what the actual measurements of most of these jacket really are.