I figured it'd be useful to do... just need to block off a bit of time. Perhaps in the next 24 hours if I'm lucky.
I've noticed that sorted sets have noticeably more overhead than the other types.
If that's true, I wonder why. Maybe is they are trying to get O(1) access? Storing it the 'default' way would be O(log n) which isn't bad, but might still be unacceptable.
Ah, I found my answer. Sets are stored in both a skip list and a hash table. So the overhead is indeed high.