Bait thrower, just a ball sinker running free to the hook is a far simpler and more effective solution, IMO. Even better with a circle hook, size 8/0 mustad Demons are my favourite, with the bait drifted back into a burley trail. Only use enough lead to get to the bottom, dependent on current or drift.
7-15kg main line depending on fish size and bottom conditions, with a leader to suit the environment you are fishing in. I fish inshore ocean waters over a reefy, kelpy bottom and find anything less than a 80lb leader, of 1.2 -1.6 mtres long, is often found wanting when a 6kg+ snapper takes off for its' cave or kelp bed.
Cheers.