Dbing in TC is easy, all you need todo is find the correct level for an Item. Example
Unique ring level 30 -> Elite ring = 98% success
Unique boots level 40 -> Elite Boots = 98% success
Unique Neck Level 67 -> Elite Neck = 98% success
I have worked with this theory for over 1.5 years now and its used to make me alot of money, when dbs where 2 - 2.5kk and elite stuff was 6kk. Now as previously stated unless its blessed or socketed just buy it.
Weapons are the worst to try upgrade in tc dont even try -> super unless you get lucky
Edit: As a side note I has this happen twice, the above method failed (on ring and boots) so I upped with a met to the next level and got a socket