Yes, temp swings are normal. Unless you are just testing with your remote probe or heat-mapping, best not to worry about the oven temp too much, it will drive you mad.
You should bend the element down slightly to be sure it is not touching the woodbox. It can cause the thermostat to use the element and woodbox as a whole heating unit. The element should be suspended just barely under the shelf that holds the wood, and the woodbox should be slid all the way back into the oven.
It is quite possible to have door leaks for a long time until the smoker is seasoned very well. Mine still leaks some after a few years.
After it is smoked up very well, time to season with a large hunk of fatty pork. You need a large shoulder or butt for this and use alot of wood again. Use your remote probe, cook at 225* until the pork is at least 195*. This can take a long time, possible over 24 hours. You will be tempted to open the door. Don't. You can turn it up to 250* if you please. Use mustard, then a thick rub of choice. Do not forget to poke a drain hole and use a drip pan.
HTH