Wow! A lot of questions, MT. First, I think it is a mistake you are ignoring nymphs and wets, especially the wets of the wingless type, but others might have a different opinion. Just remember,trout (fish) do most of their feeding, underwater.
There are many ideas regarding presentation and matching the hatch. Your prevalent question pertains to that. I will give you my take, and you will get many more, I'm sure. It'll be your job to sort it all out.
Presentation, to me, is very important. More important that actually matching the hatch. You must present the fly from the best position to give the fish a good look at what you have to offer. It must be, for the most part, drag free. Movement and exposure to you must be minimal. Many people consider fly behavior part of presentation. I do not. Once the fly is on the water, the presentation is pretty much over. You are now fishing. Fly behavior, however, is no less important. The fly must behave like the natural, like food, like it is living.
There are times when trout feed opportunistically, and other times when they feed selectively. I believe the opportunistic mode is most of the time, however there are those times, and often times certain places where you fish, that require you to not only present the fly correctly, but match the hatch as well. It is up to you, as the angler, to determine how the trout are feeding and know the places you fish, and the fish you fish to. So under certain conditions, the fish may very well refuse your Adams when feeding selectively on sulfurs.
With all that said, one thing you have to remember, nothing in fly fishing is written in stone. What we believe one minute will be proven wrong by the fish the next minute. So, keep fishing. The more you do the more the fish will teach you. There are many ways to learn more and broaden your experience that don't cost a lot. Some are free! Don't fret that you can not spend tons of money on tackle. It does not mean you won't be successful and have fun.
Mark
PS Look into the wet flies!
"I have the highest respect for the skilled wet-fly fisherman, as he has mastered an art of very great difficulty." Edward R. Hewitt
Flymphs, Soft-hackles and Spiders: http://www.troutnut.com/libstudio/FS&S/index.html