Crowns or Comets (both 15 inch) fitted with 205.65.15 will give the best comfort.
195.65.15 nearly as good for comfort and are the cheapest of any R75 size tyres to replace.
If your 75 is the daily car then I would go for 15 inch wheels at least in Winter. Last winter my saloon (205.65.15) steady as a rock, no problems.
Tourer (Unions 215.55.16) got left on the drive until snow gone. Lets just say grip not nearly as good as saloon in snow and muddy car parks at National TRust overflow parks
