Using repeater regions, is probably the best method to heal especially with IS Boxer.

Your tank is free to click away.
I mouse click on Divine Plea and Avenger's Shield.
You'll still need to spam something for the DPS, doesn't hurt to have the tank on the same spam button.

If you want, you could bind a mouse button to your Click DPS Spam button, or the scroll wheel.
Just copy an FTL DPS Keymap, for the correct assist keymap.