The widest section width you can run is dependent on aspect ratio - the lower the aspect ratio, the narrower the range of acceptable wheel widths for a given tire section width.
Go to
http://www.tirerack.com and search the 255/50R-16 size. Pick a brand then click on "Specs", which will include the recommended wheel width range for all sizes offered in that particular make/model tire.
You can then select other candidate 16-inch sizes and repeat the process. Recommended wheel width sizes are based on standards promulgated by The Tire and Rim Association.
Duke