I heal w/ WHM on gamepad.

Really if you are fine using it on other classes you will be fine using it while healing. Really the biggest thing is to remember is that if you have to change targets do it while a spell is casting or the GCD is ticking away (usually the same thing).

One thing I strongly recommend is to keep long-cooldown abilities off your main bar, and use the HUD customization to enable one of the horizontal or vertical bars and put your long cooldown abilities on there. While you won't be able to hit them there while using a gamepad, you can use this to see the cooldowns when you aren't on that 2nd bar.