Ok, I'm going to combine my posts into one post to try and make it more clear.
The width of the wheel you can fit has nothing to do with the hub, and where the hub sits. It has to do with how much space you have under the fender, including the UCA clearance and clearance when going lock to lock.
On a 65/66, and an 8" wheel in a 17 or larger size WILL fit the front. There's is enough space between the fender and the UCA to do this. An 8" wheel will also fit the rear, no dramas. Plenty of space between the fender and front inner wheel well for that.
Once you work out what size wheel you can fit, then you work out what backspace or offset you need. That is based on where you're hub sits. If you hub sits closer to the fender, you need more BP. If it sits further in, you need less BP. Same as when guys shorten their rear end to get more dish on the wheels. Same size wheel as before, but less backspace.
For you vehicle, if the front hub was stock a 17x8 with a 4.75bp would fit (assuming the wheel BP is correct as mentioned above by GT289). You said your granada setup(which I dont know much about) has pushed the hub out further towards the fenders. This means you need more backspace on your wheels. So the 17x8 4.75bp that would have fit, now needs to be 17x8 5"bp for eg.