It's certainly not a freestyle boat that Yellowcanoe is referencing, but it should respond well to subtle leans. The key is to allow the boat to turn a bit, and capitalize on that tendency. As you're paddling (since it has a seat, I'm assuming sit-and switch), the boat always has a tendency to turn away from the paddle if you're using a non-correcting, straight-ahead stroke. Thus, you'll be getting 4-6 strokes a side before you switch sides. For subtle turns, you can just keep paddling on one side, and the boat will turn away from your paddle. To stop the turn, just switch. For a more pronounced turn, you can lean very subtly to the outside of the turn--just slight hip angulation makes a big difference. You can also add sweeps--together with a hip rotation, you can slew the stern around pretty quickly. As you've noticed, cross draws are not very effective. In a cross draw, you're usually centered in the boat, and the stems are solidly planted in the water. You're pushing a lot of water with those stems. You can lean a bit in cross draws, but it is awkward, as you're leaning away from your paddle.
One thing worth trying, in order to see both how responsive leans are, and to see how far you can lean, is to paddle forward normally, and as the boat begins a slight turn (right before you'd normally switch sides to keep it straight) finish with sweep. Lay the paddle (which is on the outside of the turn) on the water with a slightly open face in a low brace position (so the paddle is skimming along the surface, and not diving). With this braced position, roll your hips to the outside of the turn. The boat will turn by itself, in an increasingly sharper arc. Your paddle is in the low brace position to provide stability, and is not causing the turn. The more you roll your hips, the quicker the turn. One thing I find very useful is to brace your knees under the gunnels--that locks you into the boat, and your position is much more stable and controllable.
Apart from sweeps, I rarely, if ever, use corrective stokes while paddling lakes and slow rivers in fast boats. For the most subtle turns, I just keep paddling on one side a bit longer, or add some hip rotation. Occasionally I might throw in a sweep. With some practice, fast boats can be pretty responsive while underway. Making them turn from a standstill is something quite different.
Your seat position will depend on your trip needs. In most of my Wenonahs over the years, that has been mostly forward in the range of the slider. In my C1W I'm all the way forward, and in the Voyager I'm only a couple of inches back. For trim, you'll find that a bow-heavy trim will result in the boat not tracking well--the stern will want to slide around, and you'll get fewer strokes per side before you have to switch. Even trim stabilizes that. With stern heavy, you're pushing water down in addition to parting it. And you'll probably be sitting well aft in the seat adjustment range, which just feels odd (can't lock your knees, boat is wider).
Except in whitewater, all of my paddling is sit-and-switch with a bent shaft paddle. The same principles will apply if you're kneeling with straight or bent shafted paddle. You'll just go faster and more efficiently with the sit-and-switch method.
Good luck--with some practice, you'll get the boat to be pretty responsive.