A few interesting quotes on entering hyperspace that may help the discussion:
Return of the Jedi, p147 (quote nabbed from SWTC) wrote: Lando pulled back the conversion switch and opened up the throttle. Outside the cockpit, the stars began streaking by. The streaks grew brighter, and longer, as the ships of the fleet roared, in large segments, at light-speed, keeping pace first with the very photons of the radiant stars in the vicinity, and then soaring through the warp into hyperspace itself -- and disappearing in the flash of a muon.
The blue crystal planet hovered in space alone, once again; staring, unseeing, into the void.
The interesting part is where it says "keeping pace first with ... photons." This implies two things: first, that somehow time dilation is overcome (probably what is referred to as relativistic shielding; I've seen references to relativistic shielding to keep one's own view of time in synch with the universe during hyperjumps, or, specifically, the effects when said shielding is faulty); and second, that a ship nearly reaches lightspeed (or does!?) before actually transitioning fully into hyperspace.
Rogue Squadron, page 2 wrote:How his ship moved through hyperspace didn't really matter--as long as it remained on the course Whistler had calculated and had attained sufficient velocity before entering hyperspace, he'd arrive intact.
Clear enough: a ship has to reach a certain velocity before entering hyperspace. This would either be dependant on a ship's "rest" velocity before the relativistic shielding was activated or on the destination, probably based on the distance.
Rogue Squadron wrote:page 133:
The hyperdrives barely sipped fuel, while the sublight engines gulped it. Running up to a lightspeed jump burned a lot of fuel, though not as much as maneuvering through a dogfight.
page 303:
"We also have a long run up to light speed so we can make the jump out of the gravity well. All this means we've got a half hour over the target. If we burn too much time and fuel fighting, we don't get out."
Both of these mention running up to lightspeed, giving the indication that this occurs before actually entering hyperspace. It does seem likely, however, that the ability to make the run is tied into activating the hyperdrive (pulling the "conversion switch" in the RotJ quote).
The Bacta War, page 289 wrote:"Sir, the ships are outbound toward Thyferra. Exit speed is consistent with that of the freighters or our own ships."
This seems to indicate that the velocity when entering hyperspace is dependant on the destination.
Isard's Revenge, page 189 wrote:A little shudder ran through Corran's fighter. A Defender latched onto his ship with a tractor beam and would accelerate him to the appropriate speed to make the jump to lightspeed. On only two engines Corran's ship wouldn't have made it, though those engines were enough to power his hyperdrive.
This one's odd in that it implies that the pre-jump accelerations are made soley by the sublight engines. Of course, we can't completely rule out the possibility that the switch was flipped but not noted, or that the velocity was attained over a longer period at normal sublight acceleration rates.
Later...
