Don't be scared!
I only have been doing this since last June and have done 4 overnights. At first I was like a new Dad.... now three kids later.....
I have a Maverick and set it on my night stand ...it has yet to wake me up.
I always do two butts around the same size as yours. I'm usually at the 13 hour time frame. I use water and do not wrap, I stuff as many coals as I can fit and use minion method. If I start around 11pm I add some coals at maybe 9 am. Check the water but most times Its fine.
I pull let rest then wrap in towel and put in cooler until I'm ready to pull it apart.
My WSM has yet to let me down....... set it and forget it..... take lots of pictures and post them.
Good luck!
don't forget to save a frosty cold beer for the breakfast tacos in the morning.
good luck, take pics, drank one fer me.
don't lift the lid...