would a pully rig be better for bite detection over say a single flapper rig and if (i may be wrong here) you lose lead on a pully dont you lose the whole rig. At least on a flapper if the lead gets snagged you get to keep the hook and the attached fish
Okay, typically if the lead is below the hook, bite detection is improved since the fish does not have to move the lead in order for you to see the bite. Short snoods (length from hook to main line) will also aid bite detection as will the use of braid as a main line.
Pulley rigs and running legers are different in that they are designed to keep the lead "out of the way" and let the bait waft around in the current.
In the pulley, the fish takes up the bait and based on the length of the pulley, it swims off before the lead actually helps to hook the fish... or in some cases, (see below) pull the bait out of the crittur's mouth!
In a running leger, potentially, the fish can swim off some distance not moving the lead at all before you realise you have a fish on... this is useful for bigger species that often attach a prey fish / bait and move off before devouring it - conger and tope being prime examples.
Paternoster rigs - whether flapping or clipped down - typically keep the baits above the lead, use multiple hooks and baits to generate a scent trail, and are use to target smaller species in clean or relatively clean ground. If you must use them in rougher ground, use wire hooks that will bend out of snags, use a rotten bottom link to the lead, and use light snoods so that if one hook is really stuck, you can pull for a break on the line attaching it to the trace, and that line alone, i.e. most of the kit comes back.
HTH...