My auto-rewind Pentax will give me 37. It seems to me that Pentax was over cautious when ensuring that enough film is taken up at the start to avoid any possibility of attempting to expose on film which has already been fogged during the initial wind-on.

However at best Pentax if redesigned smight squeeze another 2 frames out of a 36 and quite frankly I'd rather stick with 6x6 strips than have a 7th strip with only two negs on it. Besides which my Paterson contact frame will only take a 8x10 paper which is designed for 6x6 contact prints only.