Forget the sticks and get the liquid.
Here is an example.
You "paint" a stripe on the case, let it dry (very quickly in a matter of seconds) and then do your annealing. The paint will blacken AND MELT at its temperature threshold, but not below the temp threshold. In other words if you paint a stripe on a case from tip of the neck to edgs of the base, the paint will blacken AND MELT at and above the temp. threshold, but do nothing at temps below that temp.
I paint my set up cases (scrap cases that can be ruined without any problems because they are only used for setting up my annealing gizmo) with two temp stripes running from the top of the neck down to about 1.5 inches below the shoulder. I use a liquid that is above the temp that I want and one that is just below at the minimum annealing temp (something like 480 degrees) to establish an upper and lower boundry for the brass temp. When I anneal the brass, the upper boundry will char but not melt, and the lower will blacken and melt, but only down to a certain point on the case. Below that point, neither paint is charred black or melted.
Next time I anneal some cases I can take some pictures to helps explain the process that I use.
I hope that makes sense.