so, get a meat probe. https://www.thermoworks.com/Thermapen-Mk4 is the best one, thermoworks also has probes that you can use the entire cook.
lumberjack pellets are considered the best and are a great deal @ dick's https://www.dickssportinggoods.com/p/lumber-jack-competition...
https://www.youtube.com/user/howtobbqright and https://www.youtube.com/channel/UCPjkdaqksNWgA63aZfQ2bAQ are your mentors