If your using an indicator i find this IMO is the best stuff out there ..and reusable again and again
you can add or take off as much as you want to suit conditions and weight of flies etc , to suit differing depths tie one of these on your leader..
i generally use 4lb fluoro for the sliding stop knot and leave about an eigth to a quarter inch tags at each end , then mould the putty around the knot and the whole lot can be slid up and down to suit depth ,if you dont mould it around a knot or something the leader will eventually cut through the putty..