Quick candle making questions

I assume someone here has made candles and can help me out.

I’m making a piece for a Halloween costume, not an actual candle, but it seems the best way to do it is by melting candle wax and pouring into a mold. What I’m making is a simple ring, about three inches outer diameter, and two inches inner diameter. It will be less than an inch thick. Is this small enough that I can do it in one pour? (From what I’ve read online, even votive sized candles typically need two pours.)

Secondly: How will I clean the damn wax out of the double-boiler I use?

Third: Will using cooking spray on the mold be good enough to keep the wax from sticking? I also have some silicone lubricant spray, would that be better?

And lastly: How “water-tight” (for lack of a better word) does the mold need to be? It’s basically made out of a piece of plywood with short lengths of PVC pipe on it. I don’t have anything “sealing” it…will wax leak out? I figured it will a little, but the small amount that does will then just cool and seal itself, and I’ll trim it off when it cools.

One pour should be no problem. You might want to do another pour if you are concerned about shrinkage.
You can clean the boiler out with boiling water, but you might jut want to use an old coffee can instead.
Use the Silicone spray.
When the wax is melted it’s nearly as thin as water, so it will leak though small openings. Use aluminum foil and tape to seal.