So I did a tcpdump of the traffic, and it looks like rclone and usw-s003 are negotiating a ssh-dss protocol. WTF... anyway...
I then ran ssh-keyscan -t ssh-dss usw-s003.... and got this result:
usw-s003.rsync.net ssh-dss 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
And that seems to work!
For the kh-s020 server:
hk-s020.rsync.net ssh-dss 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