Thank you for the post here BobT.
The first size that comes to mind is 285/40-18 then 305/40-18.
Compared to your factory tire size (225/60-18), the 285/40-18 size is 2.3" wider and 1.65" shorter. The 305/40-18 size is 3.15" wider and 1" shorter.
Both these sizes however, are not recommended for your factory 18x7.5" wide wheels. The approved rim width range for size 285/40-18 is 9.5" to 11" and for the 305/40-18 size, 10" to 12".
My recommendation would be the 305/40-18 size with a new set of wheels.