Thanks, Scott. I know this can improve a lot and I thank you for your suggestions. I made these new videos slow because my client got headaches from my older, faster videos made 5 years ago in Artlantis 4.5, but it seems I exaggerated. Most of the furniture was brought over from the original 5-year old ArchiCAD models. I've been trying to replace most of it with better stuff from the 3D warehouse, but time is limited. Same excuse for the rest. Still, there's a couple weeks left until these videos will be shown to the general public, so I might have time to improve them if no other project fills my plate.
jsteacy, I prefer to use the "image sequence" export function from LightUp. I then used VideoMach 4 and the XviD codec to convert this .tga sequence to a video small enough to upload to YouTube (around 300 MB, quantizer 2.00).