these Rigs have been around for a Very long time,
They are used Heavily on the atlantic coast fishing for Striped Bass.
I own one, But have not caught anything with it, trying to troll.
You can add or remove hooks as needed, While trolling i would only use one hook from the centre with all the others as attractors.
as for casting??? I'm sure there is a better way to get the fish to your boat.
I have heard these rigs are great for Lake Trout, and possibly white fish trolling.
still yet to get mine fired while out for Chinook.....
~Jeremy.