If you're rigging out for salmon, consider leaders without any weight.
In my experience, if you add a splitshot to a leader, it must be close to the smelt. About 6" is perfect. If you position the weight further from the bait, the smelt will weave a tapestry out of the leader.
I only lip hook baits if using a small jighead. Only one of my traps is rigged this way.
The remaining baits are "threaded" on the hook. Insert the point just under the skin about midway between the dorsal fin and the head. Work the point forward until the bend is covered. Then twist so the point exits and faces up.
You can do the same thing between the dorsal and the tail. These baits put out more vibration but wear out quickly.
Threaded baits don't foul. That is, the smelt won't hook themselves.