I agree with both Daves. My H22 will round up at about 25 degrees, and there is nothing I can do about it. I have had a 150 genny and full main out in 15+knt winds, and still couldnt bury the rail, she would round up about 2 or 3 inches from it. I usually sail by myself, so I dont have the weight to put on the windward rail. Heeling and rounding up is most scary when its unexpected. As you sail more you will be able to see/feel it coming, and prepare. As a gust comes up, allow yourself to head up a bit. It will keep you from heeling as much.
As for an inclinometer... unless you are racing, I wouldnt bother buying one, you will know when she is sailing fastest. Just try to sail as flat as possible for any PoS.
And last bit of advice... when taking sailing lessons, have your wife take the same lessons, but not in the same class as you. She will feel less intimidated when you are not there. And then when you sail together, alternate days being captain. And remember you werent in her class, and unless you both watched the same video tape, information might have been delivered differently.
Dont be discouraged by the snarky comments. Its all in good fun, but shouldnt be directed at a noob. Keep asking questions, the real answers will eventually be posted.