One last note - also it seems that a few edges in there did not get glued together right somehow. If you use Edit/Separate to break the whole ring into individual surfaces, then use Edit/Join to rejoin it back to a solid this seems to get fixed up and some edges that were giving problems are now working after that.

So that may enable filleting of the whole model after that.

But it looks like it is going to take quite an awful lot of memory to do all those little corner pieces, you may possibly run out of memory while it is working on it if you try to do the whole thing at once. So that kind of pre-filleted approach could really be the way to go here.

- Michael