I am reading a lot of "Cure II is your last resort replies" but honestly imo if you want to learn to dps as a healer you should not resort to using it at all. Force the tank to start playing and use his cds wisely, use your other healing resources and ogcds so that you don't skip more than 1-2 Holy casts. I'd rather wipe than cast Cure II on the tank personally if I am correcting their mistakes. It is what I did when I was leveling and learning ast as well, at some point you gotta kiss goodbye to those gcd heals or you will always keep using them.