As far as I know: Bootlegs are grey market material. Live, unauthorized recordings that were commercially available by "bootleg labels"
Private recordings are the same as bootlegs, but are not put on the market for sale. They are circulated by fans for private use only - Never for Sale!
Truthfully, every one I've heard has had much to offer. I've not catalogued those that I have (and relative to what I understand is out there, I have but a handful) by date or location, so I can't tell you what's what, just that if you have a chance to get some, carpe diem.
Thanks, Jim - I'm carping as we speak...