Good idea, but here are a couple of my suggestions:
If you were filming it offline, tweak the time settings and set it to very early morning ( type in ".time 06 00 0" without "s where 06 is hours, 00 is minutes and 0 is time speed multiplier, play a bit with it and you'll get the time you like).
Next what you might do is tweak the fog bit, reduce it to about 10 or a bit more miles, experiment with it, you can find the setting in arena settings-> enviroment-> fog distance.
Things like this can greatly improve video atmosphere;]
For uploading to youtube always save the video as WMV file, 320x240 resolution, 920 kbps will do just fine, 24 bit video sample size.
Hope this helps