Glad to hear someone else is getting into Led Zep's live stuff the same way I did. 6/21/1977 was my first true Led Zeppelin concert too.
Since you mention it, one channel I can recommend is my friend Randy Butternubs: https://www.youtube.com/user/randybutternubs1209
He only uses lossless audio and saves everything in HD before uploading it so YouTube's uploader doesn't completely destroy the quality. Most of what he's put up is stuff I've shared with him, so if you find anything you like, lemme know and I'll PM you the original files when I can.