I would go with the wider wheel. The OEM wheels are 7.5 inches wide. It will make the sidewalls a little less rounded than if squished more into the narrower wheel. The tire should steer, and drive better with the wider wheel as the side walls will be straighter and less flexed. You are already go to minus one in diameter, I would not go to minus .5 in width.

 

I asked when they said I could downsize. It is guaranteed to fit though I have not tried yet. We have had a strange warm spell so we are waiting.