Suggestion: If you could assign a folder to a category it would eliminate a few steps that I spend a lot of time doing. If a category has a folder assigned choosing the category automatically moves files to that folder. If no folder is assigned to the category changing the category keeps the files in the finished downloads folder i.e. as it is now.
Categories already work that way. You can select default downloading location and seeding location for each category. Enable Categories (Layout > Categories), right click a created category > Properties > Local Files.
Since upgrading, I have noticed that Tixati chooses to pick files to download within the torrent. It seems based on size? and occasionally I have to pick through the files and add the necessary files to the download.
Settings > Transfers > Files > Always auto-select files in new transfers - turn that option off.