I know it's a bit late but in case anyone else is reading this, I'd definitely recommend bandicam over fraps. It just has a much, much, less significant impact on frame rate of games. It also has a VERY useful video recovery tool that can recover the entire video from start to finish if you have a crash, this is compared to other software normally used for recording broken videos which usually only give me maybe 50% of the video if I am lucky. Oh and turn off the box that says "skip recording when frame is not updated" because that will sometimes stop recording during lagspikes and stuff which will cause your video to skip forward and lose any commentary you make during that time.
Also, to the person who mentioned seperate audio tracks, bandicam also allows that, it's inside of the video settings when you select the secondary audio source, there's a box you can tick to record seperate wav files for each source.
I'd also personally discourage using obs as a recording software, it's wonderful for streams and podcasts but for regular videos it'd require you to constantly tinker with the software to get all your intros/outros/layouts which is a hassle and irreversible since it will record like that. It's much better for editing streams live.
As for massive file sizes, use handbrake to compress videos after you've edited them. Format Factory is also an option for compression, it is a lot simpler but the tradeoff is usually a significantly larger compressed file. You can also shrink how large the recorded file is by using a lower quality codec, such as the mpeg-1 codec if you don't mind the tradeoff in video quality which isn't too noticeable anyway if you're gonna put it on youtube. (I usually record 1 hour-ish sessions of minecraft, with the mpeg-1 codec it's about 3.4gb, with the motion jpeg codec it's about 80gb)