Happy Thanksgiving to you, too!
You're asking a lot of questions here, and I know you're eager to get your project finished. I can say that if you took the time to look around you'd find that every one of your questions has been answered in other threads on the forum or in the many, many tutorials. Since you're pressed for time, I'll try to give you a quick answer to the audio adjustment question.
To adjust the volume in specific sections of a clip without leaqving the main editor, you'll need to use keyframes. Place one at the start of where you want the volume lowered, then place another where you want the volume to be at the reduced level. Do this for every change you need and PD will automatically ramp the volume up or down to the new volume level when you produce (finalize) your clip.
Once the keyframes are in place, you can drag them up/down or left/right in the timeline if you need to make any adjustments. This is what the clip will look like:
To give you the "best" settings for you final video, I'd need to know the details of what your format your source clip is. Generally, you should get very good results using H.264 AVC and matching the Profile name/Quality to your source clip. I don't think that 1920x1200 is a standard recording resolution, and if your source is 1920x1080 and you produce to 1920x1200, you'll either get a stretched picture or you'll have black bars at the top and bottom.
As for why your previous project took 7 hours, I'd need to know
lots more details. It's kind of like you saying "why will it take 7 hours to get to Chicago?" when we don't even know where you are or whether you'll be walking, driving or flying there. I hope you can see why those details are pretty important
YouTube/optodata
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