I have a Traeger model 70 with a 3 position switch (smoke, med, high).
I could upgrade the controller with one that has an actual temperature setting, but it's 5 or 6 years old and I hate to spend money on it. I had to replace the firepot, controller and ignition rod last year...in retrospect that would have been the time to get an adjustable controller. I don't have any problems getting a pork shoulder to 195 internal (or higher if I screw up), but I hear what you're saying about keeping it hot enough for the collagen to break down.
The pictures earlier in the thread with the grey lines were really helpful. The last flat I did was like that -- with the distinct grey lines. I didn't realize what I was looking at.
I'm certainly going to try again with what I have and see if I can do a better job. I need to replace my Mavericks remote temp probe as it died recently, thinking about one that will plot temp over time so I can get a better handle on what my pit is doing.
You could always smoke it 75% of the way then move it to the oven for more temp control at the end. I know a lot of people will say that isn't true smoking but it will work. If you are trying to hit 195-205 degrees and your smoker is dropping down to 180 then it might never get there. I would smoke it to 170 ish then move it to a 250 degree oven.