Once you have uploaded your torrent, it is no longer needed anywhere on your computer
Once you have started seeding your torrent you can delete your downloaded torrent.
Just a note that uTorrent places its own working copy of the torrent in its own folder, in my case C:\Users\username\AppData\Roaming\uTorrent.
This is where the torrent gets deleted if you use 'Remove And Delete Torrent' in the torrent list
'private torrent' means basically that. It doesn't show elsewhere.
And 'preserve file order' is only when you post multiple files in one torrent. On the website, the files can look haphazard but this means when someone actually starts downloading the files show as the seeder intended
PS While I think about it, in uTorrent you can choose Create New Torrent and then just drag the file from your Explorer or equivalent onto the 'Select Source' box - saves a lot of farting about  🙂
PPS I have just uploaded a torrent using the same 'nonsense' torrent I used on another site. It is seeding nicely here 🙂