I use a 30lb on the yak. It's just a more comfortable size to use than the 60lb.
If you just want to control fish at boatside, get one of these. They work great, they're cheap, and they float.
KayakFishingStuff.com: Fish Grip
If you do use a Boga, get one of these for the lanyard.
KayakFishingStuff.com: Anchor Float