Pizza is a topic that I see discussed a lot on Diabetes forums. Below is an an example of how I would bolus based off of using the TAG method...
Pizza Huts Meat Lovers Crust Stuffed Pizza (lets go BIG, right?)
Carbohydrates: 39g per slice x 3 = 117g
Fat: 26g per slice x 3= 78g
Protein: 22g x 3= 66g
Total Carbs 117g / 15 (standard bolus) = 7.8 units
Protein 66g x 40%= 26.4g +
Fat 78g x 40%= 31.2 g, 26.4 + 31.2 = 57.6g/15 = (squared bolus)= 3.9 (rounded up) units over 4 hours
TAG = 261g
7.8 units standard bolus (carbs in meal)
3.9 units squared/extended (fats and protein) over 4 hours
Why not use a formula that has some structure?...Wild A$$ Guessing your way through life is no way to live. Give TAG a try, what do you really have to lose?. I (or a few other TAG members here) would be more than happy to explain the equation up top, I know it looks a little overwhelming.