Why not set up a send-next-click command so you can just press the button once and click the target area once without having to switch from your masters screen.

Youll have to put the spell on a bar and bind a key to the button on that bar (in wow - use < for example).

You can make isboxer listen for alt-space or whatever key combo you want and have it send the wow keybind to an atg that contains your priest. I use either a click heal region atg that contains all healers or one that contains only holy priests.

When you press alt-space or whatever you chose in isboxer, it sends < to the priest, causing the lightwell spell to cast. Then it waits for you to click an area on your masters screen and sends that same cllick to the priests screen.

Im reciting all this from my spotty memory. Ualaa is the one who could tell you forward and backward how to do it exactly.