[Pax]

You don't have to revert to bonus movement (one of the aspects of propulsion in SE4 I never did like overmuch).

Specify a movement-point rate for each engien type; then, specify that all ships require 1 engine to move. Now, one engine component will -always- produce the same number of movement points, regardless of what hull it's mounted in (like stock SE4).

HOWEVER, more akin to QNP-mods, more and more of the ship will be used up, to maintain that same speed. Then you can reintroduce pure-bonus-move c0omponents (like Solar Sails), similarly adjusted for mass relative to the hull in question.

Also, you can impose an ever-decreasing speed limit by specifying an ever-dwindling maximum number of engines allowed ... say, all adding up to generally the same total tonnage, representing the biggest engine array that can be built.

Thus, given the same mass of engine, smaller ships will move faster ... and with an upper ceiling, the bigger ships cannot simply spend more and more of THEIR space, to keep up with smaller ships *determined* to go faster.