It sounds like you are being a bit hard on yourself. If you're instructor is sitting back and letting you get on with it then chances are you're doing fine.
You shouldn't really need to fight the aircraft at all. They are designed to be fairly stable. Possibly the best thing you can do is hold your control position and see what is happening, and then make gradual changes to maintain your desired approach to the runway. Don't let yourself move the controls quickly. Less is always more!
If you are "steering" into wind gusts (for example) you may think you are keeping the wings level, but in reality you will be causing a delayed roll when the wind gust dies down, and then you will have to pick the wing up again increasing your work load. I was guilty of this during training until an instructor pointed out that if I kept the yoke centred, as the aircraft moves around, it is almost like it is pivoting about the yoke. Your hand will lag behind the aircraft so there is still aileron input but it is much reduced.
In terms of aiming point, I wouldn't worry about where the numbers appear in the windscreen, but look straight at them and fly toward them. Just keep thinking fly towards them and it might surprise you how easy it is to actually get there.
The very best thing you can do of course is ask your instructor for advice, but like I said above, he probably thinks you are doing fine!