I see two major issues here. The wide wheel is just about guaranteed to rub on your tie rod ends if you have the original style ends. Also, if you run 15" tires instead of the tall skinny 16" tires, you should be prepared for loosing several miles per hour going down the road, unless your 15" tire is taller than the original 16" tire.
Well, when I say "reduce the stance" I wanted a way for the truck not to appear top heavy and teetering on the skinny, rubber band-like bias tires on my original 16's. They look good from the side but not from the rear or front. That's my personal opinion. So, the rims I recently bought supposedly came off a 1960 Apache. Same 6 lug pattern but they are 15" X 5.5 which I believe will increase my options for a little wider and lower profile tire maybe like a 205/70R15. Time to go tire shopping. Can someone write a permission slip to my wife?