I really don't know why you are having so much trouble with your Safe. I've had mine for 2 months and done about 8 smokes on it. I don't use water and the lowest temp I smoke at is 225. Only once did it "run away" and that was only to 300. It was my fault. It was at 200 and I was trying to raise it to 250, so I opened the vent 1/4" more and neglected it for about an hour. My bad......
I actually use a ruler to set my inlet now. When I set mine to 1/2 inch open, I can maintain a temperature where it is at. It can be at 225, 250 or higher. At one half inch, the temperature is maintained. If I open it even slightly more, the temp will start to rise.
I suggest you start "measuring" your inlet vent and experiment. I keep a ruler on my prep table all the time. I also adjust the outlet vent accordingly.
I also found that there is a tiny bit of in and out play on my vent, so I always make sure that I have it pushed in when I set it.
Extremely small adjustments make a big difference in the temps.
When I open the door for any length of time and then close it, I open my vents all the way to establish a "good" air flow. When the temp gets close to my target setting, I set it at "exactly" 1/2". Of course yours may be different.
I had a large ceramic Kamado for over 12 years, so I learned what effects a small inlet air flow can have on a very well insulated smoker.
You have to learn what it takes on your new smoker. This Pitmaker Safe is even more sensitive to air inlet than my old Kamado, so I had to learn some new stuff about it.
I don't use a Guru. It may be your problem.........
I hope you don't give up.
Doc