For a 15x7 rim in the front you'll want 4.25" to 4.5" backspace (+6 to +12 offset). The cragars in the first link are 15x7's with 4.125" backspace (+3 offset) and a 225/60/15 tire, which will be cutting it very close for fender clearance. I would suspect that they might rub during some turning situations unless the car sits pretty high. I ran 225/60/15's on my '74 Duster on 15x7's with 4.25" of backspace, they didn't rub but it was very close. If those are the rims you want in the front, you may want to consider a 215/65/15 or 215/60/15 instead of a 225/60/15 just to play it safe for clearance.
In the back I'm going to assume you have a 7.25 or 8.25" rear axle (stock). Those are pretty narrow rear axles, narrower than the earlier 8 3/4's. That, and the Duster body style, is why there's so much room and the wheels sit so far in. The Cragars in your first link have a -6 offset (4.25" backspace for a 8" rim), which is good if you want to move the tires out and make the wheel well a little more filled out. Same with the wider 245/60/15. That combination will probably be a good 1 1/2" further out toward the quarters than your current set up, but should still leave plenty of clearance to the quarter. If you wanted you could step up to a 255/60/15 and you'd still have plenty of clearance, although that's getting to be a pretty tall tire (27").
Unfortunately, the only tires available in half decent sizes for 15" rims are the BFG TA's. Great for doing smokey burnouts and making it look like you've got more horsepower than you really have because they spin so easily, but lousy for actual traction. You might be able to find a set of Cooper Cobra's in those sizes, they're a little better than the BFG TA hockey pucks.
