imho, it is a lot easier to control wheelies when you clutch them up rather than just throttling them up.
be a gear higher (2nd or 3rd gear), relatively low in the RPM range, pull the clutch with one finger, rev the motor a bit, dump the clutch. don't rev it much at first and just get used to the feel of the bike "lurching"/bringing the tire up a wee bit.
as you get comfortable, bring the front up further by increasing the RPMs more before dumping the clutch and also start using your body...slide back on the bike and yank a bit on the bars (or, ultimately, preload the suspension and let the rebound help you out).
it might seem less intuitive/scarier at first than just twisting the throttle and yanking the bars, but ultimately it is much smoother and more controllable imho.
try to learn to cover the rear brake so that if you start to go past the balance point, you can use the rear brake to bring the front back down. (if you have your brake pedal set really low, you might need to bring it up a bit to be able to effectively use it while wheelie-ing).