Haha you're right; 'when it comes to boats..." It's a fixed keel. I think theres something like a nearly a ton of lead down there. Which is why I am wondering about the extreme heel in only 15 mph winds...
There are a lot of great answers/responses here. I am going to try all of them. I think it may just be that I need to start controlling the traveler/mainsheet more (or at all). I never touch it. I usually pull it tight and let it swing freely on the traveler from starboard to port as it wishes (when I come about).
I usually single hand and I'm in way over my head already with the tiller, jib sheet and halyard in my hand. I can't imagine messing with the traveler/main sheet as well especially in the gusty winds we get and with this nasty heavy heel that I'm dealing with. It's just too much. .......
There are two halyards (For raising the main and Jib.)
If' I'm single handing, I don't mess with the halyards while I'm sailing. I have the job sheet over the tiller and in hand so that I can release the jib if heel is excessive. I also have the main sheet handy so that I can let that out.
Much of how you should adjust things is relative to your point of sail or which way your apparent wind is coming from but a few things to understand:
If you have a boom vang, adjust that before going out. I think that the boom vang has two purposes. The first is to adjust mainsail twist and the other is to take some of the tension off the traveler system so that IF you need to release the main sail, it's not jammed. You should have a working traveler (for what it's worth) as they are pretty much standard on all C22 boats. If that traveler doesn't slide then your main sheet is way too tight. The traveler can be set so that it slides a bit to either side when you tack and your main sheet can be a bit loose so that the boom swings to either side some more when tacking. This may make a big difference in your heeling.
Understand your jib sheet cars. They adjust twist on the foresail. For example, If you want less heel, move the jib cars back. This puts the center of force on the jib sail lower and less heel. The foresail is a sort of wind power amplifier for the back side of the main. If it's too tight, it slows the boat and gives you unnecessary heel.
The combo of jib and main twist in the sails an have a big effect on your heeling issue. This paired relationship is also important later on as your confidence wants more speed. The amount adjustment of these basic controls will change your comfort and your speed.
I may rub some wrong but I feel that experienced sailors often speak of trimming for the most speed as being safer. But, if you aren't sure of the use of a particular control, this could potentially be dangerous. As an example, there's nothing quite like an accidental hard jibe with a very flat main.
Your boat doesn't really need to heel more than 15 degrees in 15 kts of wind. If you are heeling too far then maybe try sailing with jib alone until you feel safe and you understand the controls of that sail. Then reef the main and learn to sail with those two together.
Also, learn to use tell-tales on your sails and read the Windex if there is one up on the top of your mast.
Your own suggestion of getting a trained first mate is a good one. Ask questions as you need.