How much does the mouse weigh? At this point you're aiming for 10 to 15% of the snake's body weight, so an 80 gram ball python should be getting a mouse that is between 8 and 12 grams. Another way to determine size is that the width of the mouse should match the widest part of the snake. After giving him a few days to chill, I'd try F/T again with the hairdryer method with an appropriately sized mouse.