In torrents with few seeders and lots of peers, I risk having the seeders go offline and being unable to continue the download. In order to minimize this risk, I would like tixati to prioritize downloading the pieces whose health is below 200%.

In order to save processing power, I would like Tixati to only activate this feature automatically if the number of seeders is below a certain threshold.

Tixati works this way already. I think most torrent clients prioritize rarest pieces first, or random if there are more pieces equally available.