tips for waxplay

My sub and I went to our local sex shop this past weekend to get candles, which we were excited about, but as we were checking out the person checking us out mentioned that the candles need to be used at a certain height. They said they'd had people bring the candles back before upset and burned because they had gotten burned (literally), which was good for them to tell us, but also concerned us. The box says to use them from at least 36 inches above skin, but we want to be super safe, is there any other advice y'all can give us? Is there a maximum we should let the wax pool before it drips, should the candles be rotated, is there better areas to drip them on, etc.

ty fam :)