Nope. If it was curated it wouldn't be much of a bot. That's how most bots are, the owners just retweet the really good ones.

One idea would be to focus on certain keywords, but you'd miss a lot of interesting stuff.

I don't know if I agree on your percentages though. In the first 3 days, I read stuff about eugenics, Shackleton, a woman declaring martial law on a town (first time martial law had been declared since Civil War), etc.