firecrackers question

greetings, i plan on making 4 firecrackers with some bud tonight and have a few questions

1: i could not find nutella peanut butter witch i heard works the best for this, but i did pick up smuckers organic creamy, and some saltines for the crackers. will this work ok?

2: from the post i am reading it says to preheat at 320, how long should i let it preheat before i put the crackers in and turn it to bake?

3: does it smell? my parents will be home and dont mind weed as long as i dont stink the whole house up.