You have some interesting challenges. Not sure if this helps or not but when I include a candle holder with candles, I make sure that it is one with a rim, just incase of overflow and that it is about 1/4 in larger in diameter. Candleholders with spikes add to the stability as well. I also try to test pillars by burning them for five to six hours at a time. As for wicking, you might want to wick down. For example, recently, I have been testing HTP wicks for a 3" candle I want to sell. I have found that for me, under ideal conditions, a HTP 83 wick is super. The HTP 73 also burns well, but leaves a little larger rim. So I am going to wick down to the 73 because I know that many don't hug their candles or straighten the wicks as they burn. Hope these suggestions help. Sounds like an exciting project. The owner should also be made aware of dangers. The only thing that I find interesting is adding FOs around food aromas.