I kayak fish and last year I switched one reel over to leaded line to help keep spoons down without having to add so much weight.

I don't trust the weight of the spoon alone to keep it down. W/O weight, I find they will ride up to the surface.

I will also use a diver/flasher and spoon behind my kayak. Adds a lot of drag, but gets you down to the fish!

Good luck