Okay, I've got an idea. Why not anticipate a thorough melting and use a pre-melted candle?

Find or cut a common nail just the right length to stand up inside a 35mm can (or the container of your choice).

Melt wax into the container, standing the nail up in the middle before it hardens.

In practice, you'd remove the wax, pull out the nail, then insert a length of wicking (that you'd carry separately).

If the whole thing melts and the nail shifts, at least you've still got a way to make a new wick hole and insert the wick.

Plus you've got a way to carry an extra nail.

Sounds good in theory, but I wonder how hard it would be to extract the candle from the container, and the nail from the wax. And will a candle burned inside an opaque container become ineffective once it burns down an inch or so?

Sounds like a scientific experiment in the making.

Bear