Another way of not killing your mullet with the cast out is to do the following,
you get a returnable slide for leeries, cast out, clip the slide on and yes let your mullet swim, by cutting the tail it will stay at the top.
or
just use a QUALITY snap swivel (like you use to quickly change between lures), it does the same thing and is what we used for many years targetting Leerie of the Harbour wall in PE.
The thing with both of these, you have to be quite a bit higher than the water (like on a wall or rocks), the higher your rod is the better.