Hello, I hope upload speed is automatically adjusted by download speed. global, per task.
I put many torrent tasks in Tixati, even not 100% healthy ones. so, If there no data incoming, but, only upload. it takes my bandwidth more than I think.

I'm not sure from your description if that's what you want, but you can reserve a big percentage of upload to "trading" - i.e. prioritize peers who also upload data to you.
The setting is under Bandwidth, Advanced.