To create continuity around the candle vs having an overlap you can cut the paper to exact measurements vs the two pieces over lapping and then fold it so the seams meet up perfectly and stamp over the seams and then cont. to stamp everywhere else, then add the embossing powder and continue on it might not line up perfectly but it will seem almost seamless :)
I've read these kind of candle projects can be a fire hazard, so one suggestion is to burn it until it pools, then put in a tealight. This way you can keep the candle forever.
Been using this technique for years and never once encountered a fire hazard with these. When I use a fancy paper napkin the middle burns and the outside stays, once the candle has burned down a good bit I then add another smaller candle to the middle, like you suggested
Edna Pendleton there is a tutorial on RU-vid that someone used a fake candle. Her is the link to that video ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-nQ10-cV2BOY.html. Or in the search button type stamping on battery operated candles.