The use of mpeg format made a substantial difference. However, using a 1320 x 1320 (vs a 1320 x 1200) working field makes a substantial difference in filling the dome.
In addition, a powerful vertigo-inducing effect can be seen by simultaneously running two layers of animation, one moving clockwise, the other counter-clockwise - the title toward the end of the 'second' set of swirling images set some profound middle ear activity into play.
Sony Vegas 9 as a video editing software does not allow for greater than 800x800 resolution, however. For HD 1080 level of clarity, that means going with the next version of Vegas, and a Platinum one at that...so much for budgetary constraints this quarter!