Welcome here Q-K. There are lots of various wheel options and threads here. If you search "wheel offset" using the forum search, you will find a wealth of information that will likely impact your decision. The best approach might be to find the car that looks exactly how you want yours to appear and ask that owner for his wheel details. Personal preference plays a huge amount, as of course does proper fit. Too wide will cause issues on the fronts (not so much an issue on the rears), but what you propose should be fine. The rears you plan may be on the narrow side considering many of us are running anything from 295 up to 335 widths (I have 295/50/15 on 10" wide Campys plus a set of 335/35/17 on 11" wide repro wheels and both fit the rear perfectly, especially when the stock spacers are removed from the springs.
Please start a thread with some details and photos of your car. It looks pretty nice from the avatar.