I've now got most of it. I'm going to try one more time when my monthly download quota resets, but I think I have the bulk of it - last score was 40 errors which is best I've gotten. The folder is 45,000+ files at 1.7 GB.
Also, none of the errors hit the pages I'm most likely to want (missions, powersets). I will probably keep using my offline copy as resource for a while to find out if I am missing anything else and just manually add to it as needed. It's not like the wiki is disappearing anywhere, and I can handle finding a few pages missing during a game - can look them up on phone is really needful.