That's why it's called "fishing", not "catching"
From your other posts, you've really only just taken up fishing like this? You are probably going to get some stick for trout fishing without the fly, but if the methods you are using are allowed where you are fishing, that's your business. The biggest objection to these methods is that they can be too effective, but it doesn't sound as if that is your problem!
It sounds to me as if you don't really know what you are doing with the float tackle and simply lack experience with the spinning. The depth you spin at is largely a function of the weight of lure, speed of retrieve and time allowed for sinking. To fish deeper, use a heavier lure, allow longer to sink before retrieving and reel in more slowly. Float fishing properly is beyond what I can explain here, but any good book on coarse fishing will fill you in.
The main problem is likely to be lack of watercraft, and that only comes with experience. The where and when and which method to use is harder than knowing the technique.
You will struggle to find literature on fishing for trout using coarse fishing methods, though, because by and large it isn't something serious anglers do. Almost everyone who fishes for trout (and knows what they are doing) fly fishes, and almost everyone who is good at coarse fishing would rather not catch trout by those means.
Must admit, if I were where you are, and fancied some sport (and perhaps something for the table?) I would take my spinning gear to the sea.