The ideal rig for livelining from a boat or kayak is the Tournament Trophy Fish Finder Slider in 24, 30 or 36 inches. Whichever length works best for your rod and reel and of course considering you will be in a yak.
Put the Fish Finder Slider on your main braided line. You can then either attach a Coastlock Snap Swivel to the braid and just clip on the rig or tie your main line directly to the barrel swivel of the rig.
Circle hooks are perfect for boats and yaks, I personally prefer sizes 7/0 and 8/0 depending on the size of the bait. Just make sure the point of the hook is exposed and don't be afraid to let the fish move off before taking up the slack in the line and applying pressure.
True Circle Hook Story: I was field testing a new reel a several years ago, I had cast out a short distance when the reel popped off the rod's reel seat leaving me with a reel in one hand and the rod in the other. Since we were drift fishing I immediately put the reel in free spool and also pulled a lot of line off the reel spool and got to work at trying to re-seat the reel. Once that was done I started to crank in the extra line and surprise - there was something pulling back, it was a striped bass!
BTW The reel manufacturer did a small redesign of the reel so it would seat better and now it's one of the most highly regarded and popular American made reels on the market.