So no practical experience in the Spot round admission but I will tell you some facts about it.

In spot round you will never get Core branches like Mechanical , Electrical , Computer Science etc.Outside Delhi Category requires more good rank as compared to Delhi Category . Delhi Category means you have passed your 12th exam from Delhi , dont ever get confused it with state residence .In first semester ( maybe 2nd also ) , everyone teases you { either directly or indirectly } if you come from SPOT Round. After this you become integral part of DTU since you become part of selected Branch that you opted.As far Rank List is considered see Cut off of previous years to get an approximate idea .

there are less chances if seat matrix is zero, but still you should go for the spot round as there are still chances