If you think you should be having bigger hits try solid pva bags, I found these can get you much quicker bites, I've had takes while I am still settling the line down, and quite often within minutes of casting them,
I had a 10 fish hit in 24 hours earlier this year it was exhausting, I was spodding constantly to keep them in the area, I agree with Yonny it's probably more down to baiting than rigs, I would create one big spot and fish at least 2 rods on it rather than spreading them over the whole swim, or 3 in a line, get them competing they will slip up more