Controlling heel angle when overpowered is completely different; it's done primarily with sail trim. The Thistle has a huge main; we are at max hike in about 9 knots of breeze, and we are hiking just as hard in 18 knots. Through the entire range, we adjust the sails to keep the boat balanced, trimming in the lulls and easing in the puffs, all while fully hiked. The J/24 genoa is big; for puffs we ease it as often as the main, and then we trim in both sails for a lull. I usually have my hand on the genoa winch handle and grind it in before I pull in the main. I also pull on the backstay in a puff in the J/24, and ease it in a lull, and occasionally I will play the traveler. Adjustments will vary from boat to boat, but the overall concept is universal; once we are already hiking, we constantly adjust our sails to keep that constant angle of heel.
Once I've established the ideal heel angle for a boat and conditions, I'm willing to modify my constant-angle-of-heel rule in order to help steer the boat. If I want to head up, I use leeward heel, and to bear off, I over flatten the boat. In lighter winds, I steer by using crew weight movement to heel up or flatten, just as we would in a puff or lull. And in heavy winds, we continue to hike full, but steer by easing or trimming. Steering by changing the heel angle reduces rudder movement, and thus is fast. Communication to the driver and trimmer is critical. For example, the forward crew will countdown a puff (or lull) with, "Puff (or lull) in 3, 2, 1, puff on." And even better, they may even put some qualifier on it, like, "Big puff, looks like a header, in 3, 2, 1, puff on."