nailing baits hard to the seabed.

[codcatcher3000]

i often read about nailing baits hard on the seabed . i also use rigs that are meant to do so such as up n over (long n low) , pulley dropper , running leger etc. my question really is how long should the hooklength itself be and would yourselves add a split shot to help keep it on the seabed? also how long is ideal for these rigs(hooklength wise) for when the sea is having a roll on ? which rigs would u say is best to achieve this result? thanks in advance