This gives initial engine thrust of 165 * 1.5 = 247.5
The Wolfen has an initial mass 46 (30 hull, 11 armor, 5 devices) and thrustRatio of 13
Gives engine thrust of 46 * 13 = 598
So the Wolfen is currently both lighter and has a much more powerful engine.
The game already does this by calculating accelleration (thrust ratio) from the ship's total mass. As the freighter has a 150 ton hull, adding 40 tons of armor has much less impact than adding the same 40 tons to a light fighter.
Currently armor mass is effectively meaningless as all nearly all armor is "light" (i.e. fits on the Sapphire) and has little impact on maneuverability as it weighs less than the ship hull.
If there was a wider range of armor masses I would generally expect the hp to be proportional to mass (double the mass, double the hp). So I'd basically have the choice of flying a fast & maneuverable ship, but would have to use that maneuverability to avoid being hit too much. Or get heavy armor with two or three times as many hp, but pretty much give up on being able to dodge anything.