I know the general policy of putting less air in the front tires than the rear. Does that change at all if I have different sized tires in the front and rear? I have two vehicles as follows: 61 Rampside Pickup 205/60R15 front 225/70R15 rear 65 Monza Convertible 175/65R15 front 205/65R16 rear How would you inflate the tires on each of these?