Experiments and results:
60 mass, 100m long, controlled from core/center 0 thrust: ~12 seconds to do a 360
60 mass, cube shaped, controlled from core/center, 0 thrust: ~12 seconds to do a 360
60 mass, cube shaped with 237.3 thrust controlled from core/center: ~12 seconds for a 360.
60 Mass, 100m long, controlled from core/center, 237.7 thrust: ~12 seconds
60 mass, 100m long, controlled from core/center, Side facing thrusters at the far points of the \"ship\": (odd note, the animation for the engines still points to the rear despite making sure thruster is facing sideways) ~12 seconds
60 mass, 100m long, 237.3 thrust Controlled from the cockpit at front of ship: ~12 seconds
60 mass, 100m long, 237.3 thrust, Controlled from rear of ship: (rather disorienting controlling from the rear) ~12 seconds.
Conclusion: the only thing that matters for turning (as of the time of this posting) is the mass of the ship. Not where you control, nor how much thrust you have.
Hopefully the turning physics will be improved, either by adding \"Maneuvering thrusters\" or making turning physics be based off of thrust/mass so you can design more maneuverability or more shields/weapons/whatever into your ship.