I need help with rendering Fraps videos with Sony Vegas

I got a GTA IV video recorded in 1680x1050 resolution and aspect ratio 16:10, which I have edited, added music to, etc.

Now I just want to know the best settings to render it with for YouTube, in HD quality of course.

I have already done it once with these settings:
Video Rendering Quality: Best
CBR (Two Pass)
WMV 9
HD 1280x720
Video smoothness: 100
Target Bit rate 10 M

It's a 3:28 minute video and 312 MB.
In a small window like the size YouTube shows them in by default, it looks good, but in full screen the raw Fraps video looks much better.

Easiest way would have probably been to have the graphics settings in the game at 1280x720 resolution and aspect ratio 16:9, while recording, but it looks like crap, and for some reason 1050 runs better than 720. (lol)

I want it to look awesome in full screen too.

Oh and also.. what's the best audio rendering settings for YouTube?
I got one Fallout 3 HD video uploaded, but the audio isn't perfectly in sync with the video. YouTube messed it up.
http://www.youtube.com/watch?v=zbcOGG1iqvo&feature=channel_page