Basically, the "1 click frame servicing using handbrake" is a quick way to create higher quality and smaller file sized YouTube videos based on Musicvid's original 2 step process "A Better Method"
I personally used the "A Better Method" for years and have recently adopted the "1 Click" method. The "1 Click" takes some time to set up but is a huge time saver in creating great looking, reasonably sized YouTube videos.
The video quality and smaller file size is imho much better than the .mpg renders generated in Vegas.
Try a stock Sony AVC "internet" profile of 8Mbs or higher, that matches your project. Most of the threads on the subject are guys who have some delivery or bandwidth constraints for getting the bitrates as low as possible. If you upload 8-24Mbs mp4s you pretty much don't need to worry about anything. Google just reconverts anything you upload with a high bitrate to the correct bitrates. The main reason to upload more bandwidth than needed, is to make sure your compression artifacts are a small as possible. YouTube will introduce plenty of compression artifacts for you, you don't want to double up on them by cheesing out on your upload time. Also picture noise=picture change=the need for more delivery bandwidth. The less noise in your images the better the compression.
With YouTube you are talking:
720P about 2Mbs
1080P about 4-8mbs
4K is about 15Mbs-25mbs with a new version of mp4,h265, or VP9
Youtube handles higher bandwidth codecs including:
XDCAM 422 and EX - .mxf and .mp4
Yes. I have tested each one of those codecs before posting. I have had the same experience as you where things change and there is no notice.
The current YouTube upload limit is 128GB, so they are rigged to handle uploading the large file sizes of Pro end codecs. This is also more than likely due to the increased file size of 4K content too.