I've heard the following (but haven't tested it yet..) :
The most important thing when baiting up is that the circle's point have to be proud and the "gap" between the hook-point and hook-shaft as unobstructed as possible, for the hook to work.
An effective way to achieve this, is to cut a piece of fillet (tiger, bream, bulldog ect.) into a strip of about 2cm wide, and about 6-10cm long, tapering toward the other end to form an elonginated triange. The circle-hook is inserted about 1cm into the fillet through the middle of the wider (2cm) end.. The baitstrip thus hangs in the bend of the circle-hook thru the one (wider 2cm) end, and the loose end dangle below, hanging free.
This gives a nice life-like "swimming-action" to the bait while drift-baiting, and ensures that the hook itself is not obstructed by the bait. The only down-side to this method is that the tiger might only bite on the free end and thus "short-biting" the hook.
Hope this makes sense.