My suggestion would be to explore other options for a smoker.
I have a Bradley Digital 4 rack and it will smoke product well when it is working, however they are absolutely rife with problems.
You are right, the temperatures will fluctuate up and down from the temp you have selected by as much as 30 degrees up and down. The element in them is known to fail, the so called smoke generator is a bit hokey and has a troublesome cheap micro-switch that also fails. The pucks are expensive and often do not burn correctly as the feeder does not perform as designed.
Many people who operate these products upgrade the element or put a second one in, modify the feeder and purchase an Aubern PID to enable the unit to establish a set temperature and hold it within a few degrees for the duration of the cook. Couple of hundred bucks extra to get what it is designed to do.
I have included a link to the Bradley Forum. If you scroll to the bottom of the page you will find the most recent posts. Monitor those for a week and you will see 50% of the posts are people trying to find fixes for the product. Look back in the history of "troubleshooting/problems". There is enough reading to keep you busy for weeks.
It's unfortunate because these are a Canadian product, Delta BC. For the price you pay you will not get good value or reliability for your dollar. You can buy a full fledged kitchen stove/range for slightly more than the cost of these smokers.
That is my experience and opinion with Bradley. Apparently their customer service is good but it would have to be considering all the issues they have.
Have a read:
http://forum.bradleysmoker.com/