once you put the ladder bars and floaters on the leaf springs merely hold the car up.this will work fine especially on the street.leaf springs alone can wrap up and cause wheel hop and other issues.some times slapper bars can help . with ladder bars the rearend wants travels in a different arch then when bolted solid to the leaf springs,thus the need for the floaters.they allow the rearend to move without binding.
but leafsprings are heavy and do not allow the chassis tuning advantage of coil overs.coilovers also require some sort of track locater to control side to side movement which sometimes can cause street driving problems.not an issue on a drag only car

i have done it both ways with no problems although i give the ladder bar/coilover set up the