I tried to do something like this in the past with other games, here is some advice:
The 30 minute length - PERFECT
Try writing a script, talk about specific aspects of the mod, having a script written will prevent you from stuttering and always make things easier.
Place your mic about 2.5cm LEFT/RIGHT of your mouth if you hear the "P" or "PF" every time you say something with the letter P.
Talk to the screen, like to a person.
Now video related (I'm pretty much giving away my secrets but whatever).
Turn off AO/AA/whatever, since the viewer will never truly see the amount of graphics you see, but keep the textures, filtering, shaders, models at max since that is really noticeable.
Record with FRAPS at full-size in a 16:9 ratio at 720p
Make a test and determine your average fps IN COMBAT so that the CPU is stressed.
Lets say you have an average of 55FPS (no lower than 50 and not higher than 60), tell fraps to limit the FPS to 52.
If you have more hard/hybrid/solidS drives, make FRAPS save the video to a disk drive which is NOT a system drive. (That way you gain 10 fps atleast when a HDD is in the question).
Download Handbrake and select your video, and tick "Web optimized"
This encoder is amazing, my last video was 42 seconds and it was 132MB, it was reduced to a mere 3.67 MB by the time it made it to YT, (It was not HD tho) and the compression is very good, since it basically looks the same as the source video.
Expect HUGE files, my video was 512x384 (half-size recording of 1024x768) and lasted 42 seconds, in size it was 132 MB.
That means 3.14MB for each second of footage, so at full res it would be 6.18MB, your resolution is a bit larger at 1280x720, so lets say its 6.3MB every second.
30 mins * 60 secs = 1800 secs * 6.3MB = 11340 MB - You will need 12GB or more of space on the other drive to record un-interrupted.
Now if a 132MB vid is down to 3.67MB the video is almost 36x smaller.
12GB / 36 = 333MB=Less pain to upload and process the video on YT.
This CHANGES a LOT with different resolutions and number of FPS.
Simplest program, and records uncompressed so less CPU stress, and ultimately gives great results when used with handbrake.
Basically like FRAPS' little bro that cleans up after him.
Why the 52FPS limit?
This varies depending on your FPS. Yes I know its an awkward number, but like this you almost completely remove frame drops and stuttering.
And why 52 if your avg was 55?
Handbrake removes 2 FPS as a part of it's compression, its unnoticeable but does the trick as far as file size goes.
The calculations above might be COMPLETELY WRONG, I was recording at 720p CoP and the video was compressed from 5.4GB to 300-ish MB, while on the other hand, I recorded Crysis at some other res (I can't remember which one) and the video went from 3 GB to 1GB.
I tried compressing a YT video once and it GAINED in size (dunno, maybe it was already compressed).
I somehow doubt the 30min video is gonna be 12 GB since FRAPS is full of "suprises".
Someone remind me to post a "Pro-ish recording/screen capture" tutorial in the future.