Next time try the birds skinned, it most certainly lets out a bigger scent trail, if the fish can get onto a scent trail faster your bite rate will increase, the best i have managed to get it down to and keep it there with out a feeding spot is between 15 and 20 min through out a 4 hour period. It took me an hour to get my system right tho. For me i like to see how fast i can get a fish to bite, it has taught me a great deal on feeding behaviour, how to judge a current or where that scent trail is going to move to. I have also played around to see what rate the scent will travel, but this is a work in progress.
If that is the deep spot on the dam GC fish it. I would position baits in various areas around the willows. But the depth is good and the structure sounds fantastic, are the willows dead or alive? I would go with the baby chickens and platties first, see what your average size of fish is and than prepare a carp bait. I would find where the smaller fish are feeding and than cast the carp away from there, but still in the deeper area. Reason being is the big old boys don not want to play with th energetic and noisey youngsters. They want to realx in peace and quiet. The inelt will be a great place to fish as fish of all sizes will be together there as it will always be an active feeding site. You will also get big carp there. I have found that i now fish further back from the inlet, my inlet at midmar i fish for 10kg fish close to where the umgeni enters, but for larger fish i will fish the wider water further away. My reason for this is that the big fish again want a big meal, so there prey will be feeding off smaller fish closer to the inlet and they will go in there to feed but will hang back when not, also the fish they prey on ahve to move around to get to where they want to eat, so have to go past certain areas. I am doing a bit more work on this theory over the holidays. Live bait will be my bait of choice.
Withn the drop off there, do you have a fish finder? I would scout that drop off, i love to fish a sloping bank. I have found that given the barometric pressure fish will hold to different spot on the slope, but 8 times out of 10 there are fish holding at the bottom of the bank, if you find alot of bait fish in the shallows than the bigger fish will be using the deeper water as cover and abushing up into the shallows. But your right, from your description the area screams barbel.
Just a suggestion on your carp bait, increase the scent, i like to cut my baits under the jaw and bash the head in a bit, yes you are getting scent from the dead red and you are from the guts but crush the fish a bit more get some other scents going. Also how many sprays of dead red did you put in the gills?