for rays an ddoggies I always use a pennel rig, but then again I use a pennel rig most of the time and never really change from it, sometimes use a 2-3 hook flapper but only when the rays or doggies aren't biting so I go for other misc fishes.
My favorite rigs are: 3 hook flapper for general scratching. Long and low clipped pennel for the rays, pulley or fixed paternoster pennels for cod (usually with rotten bottoms), long and low clipped for smoothhound and a float rig or leadhead with earworm or sandeel for pollock.
The majority of the time a combination of the ground conditions and what you want your bait to do will determine what type of rig you want. Species will determine the hook size.
Good advice from divvy and weepete. When your starting out it is mighty tempting to overcomplicate things.
A simple two or three hook flapper as a rig for general fishing and close in. A pennel or single clipped down rig for distance or rough ground.
Hook size is important and sharp hooks is more important. 2/0 hooks are a good all rounder but down to size 2 or 4 for flounders and sole. Small sharp hooks can also hook up when the bass are being a bit picky with the bait they pick up. Bigger hooks for bigger baits and the 2 hook on one trace pennel for bigger baits still and a better chance of hooking up.