For lower temp smokes, you are going to want to use chips or slice some slivers from your wood chunks to get smoke at lower temps.
I used to try to do those stepped up sausage processes, but they took forever when smoking that much meat. I usually smoke 25-28 pounds at a time and with that much cold meat in the smoker, it takes a while to get the meat up to the 130-140 range even without using the stepped up process.
This is what works for me. I put my cold meat into the pre-prepped smoker (foiled, wood added, etc) and run with these steps:
1. Smoke at 45 minutes at 150 degrees.
2. Increase temp to 200 degrees and smoke for another 2 3/4 hours.
3. At the 3 hour mark, most of the smoke production should be done. So, this is the point where I add my Jerky Dryer.
4. I continue to smoke until the sausage gets to the 150-155 range. This usually takes about 8 hours.
5. Move the meat to an ice bath, or if it is cold enough out (I smoke a lot of my sausage in the cold ND winter months) I just hang my sausages back up on my rack and let them cool in the garage or outside on my deck.
I am not saying that this is the only way or even the right way. But, I have tried several different stepped up methods and they take a lot longer and I have not been able to see any difference in quality/taste. So, this is what works for me.
I use this same process for Snack Sticks as well as larger ring type sausages or summer sausage.
You definitely need the jerky dryer though. So, I am happy to hear that you have that in your plans.
Hopefully this helps.