Winter tire size options for 16"

Hi guys, I have the prius C in the 16" tire options, and my stock all seasons are sized at 195-50-16. In looking for winter tires, I found this stock size to have very little selection. A local tire shop suggests 185-60-15, saying it is "the same overall diameter and does not put less/more strain on any of your vehicles components. This is the correct size for your Prius c". Other threads on here have suggested 185-65-15, 175-65-15, and even 195-55-16 (although I was under the belief you should always go down in size for winter tires).

My main concern is I thought the C with 16" tires has a different drivetrain (or something) that makes the turning radius wider. Would it not "screw things up" if I went down to 15" tires for winter? And among all these suggestions for alternate tire sizes, which one is "best"? Who is right and who is wrong? Thanks!

 

I have read to never go up in size for winters, and if I want to save money I could minus-size my tires. There's a good page on tire rack that tells you what sizes to use (TireRack.com Search Winter / Snow Tires By Vehicle at Tire Rack)

With that in mind, I'm getting a set of Winter Claw Extremes in 185-65-14 for a pretty good price. This size is smaller than stock diameters by 0.89%, according to the tire size calculator on 1010tires (www.1010tires.com/tiresizecalculator.asp)