Artist recommends using 4" dry wall screws inserted at an angle to hang his art. This does not look sturdy. Any ideas ? The art is a large ceramic tic tac where 2" of the screw is inserted in one end for hanging purposes.
You are much better off using an anchor that is probably way over engineered for your artwork. For instance I would get a 150 lb anchor (or even better) like this. If you go straight into the stud you can really need a thicker screw for a lot of weight or it could sag. Problem I would foresee is the hole in artwork for screw not being big or deep enough for said screw.
OP commented that each piece is only 1 lb. At this tiny weight, anything will do the job. If you can guarantee no one will touch them, any kind of nail or screw is perfectly fine. If you need something a little sturdier, use any kind of drywall anchor you can find. This will prevent movement and damage to the drywall if any of the pieces are bumped.