Re: Mass, volume, and Warpdrive question.
The effect is seen the greatest in "The Voyage Home" where at Warp 2, the Klingon BOP is no where near the speed of light as it breaks orbit. (So in TOS at least, warping into a planet would make the ship slower than light by the time she impacted.)
This is purely conjecture as there is nothing seen/heard onscreen stating the ship does not reach lightspeed. If we were to rely on interpreting the visual effects then we would have to admit that most of the time we never saw ships going faster than light speed in all of Star Trek.
Baby, you and me were never meant to be, just maybe think of me once in a while...