One application of wax is sufficient for storage. Actually as the mold ages it improves in how well it will release a part. Later, when you plan to lay-up another part, wax the mold. When working in polyester, in an aged mold, I have success with just wax for a release agent. When working in epoxy I always use wax, and PVA. Here's another couple of suggestions: use compressed air to pop your parts out of the mold, and if necessary use soft thin strips of material to wedge into the edges of the mold. They make wedges for just this purpose that can be bought from fiberglass supply houses, but you can use thin strips of aircraft plywood, with a bevel on the edge. Sometimes just getting a wedge in the edge of the mold provides an opening to inject a blast of air. As has already been mentioned, there are hundreds of tips on how to make glass parts, and in many cases there are more then one way to accomplish the same task. For example it has been discussed whether to spray, or brush the PVA in the mold. I prefer to spray, but someone else posted that they prefer to brush. Another trick I like to do, is warm my mold in the oven for about 5 minutes (lowest temp setting) before spraying the PVA, which makes it dry quicker, before it can run. In the end ask question, try different ideas, and decide what works for you. Good luck.