Gary is incorrect about the definition of Offset. Offset is not a measurement from wheel arch on the car. Offset is the measurement from the center of the wheel to the mounting surface on the wheel. It is a wheel measurement and has nothing to do with the cars wheel arch location. Offset can be negative or positive and is based on which side of the wheel (inner or outer) part of the wheel has more or less distance from the mounting surface of the wheel. A + number means that the wheel inner edge has more distance from the center of the wheel to the inner edge Thant the center of the wheel to the mounting surface of the wheel. Gary’s factory offset numbers look to be ok.
So if you consider a wider wheel, then you need to consider the additional width in the offset number and how that positioning of the inner and outer position of the wheel can impact your clearance of the fender arch and the suspension/brake caliper.