...but when I import my slate, it's very jumpy...
Import it to where? DVD Architect?
What render settings did you use?
Maybe it's your computer that's bogging down.
What kind of CPU do you have in it?
Also, what codec or settings would you suggest...
A DVD will only take MPEG-2 files for video and AC-3 or PCM (WAV) files for audio.
Even video up to about 2 hours.
You need to set a custom bitrate when you render anything over 70 min. from Vegas.
Edward Troxel covers these steps quite well in
Vol. 1 Issue #7 of his newsletters.