I consider myself a student not a master and learned mostly by mistakes.
I love smoking or as some refer to it Barbequing... When I travel I make a point of sampling local BBQ. It's my thing... I've experimented quite a bit with it over the past few years in both technique and foods. Everything from various meats, cheeses, veggies, nuts and herbs & spices, salts, pepper. Even desserts.
I've got two of the side firebox smokers, an electric and I also use a small weber. The smokers were from garage sales and the weber a gift. I've also got an outdoor fireplace with grill insert and have also done in the ground pit smoking. When I have the time and resources, I have the plans for one of those outdoor Italian wood ovens... Someday
Sometimes I start smoking the night before/overnight or gotten up at 4 am to have stuff smoking all day on a very low heat to be ready for an early dinner with guests. Professionals/restaurants often do it overnight for the next day's service. Cold smoking can go over weeks time but to me that is more like drying/curing/preserving. The results are a thing of beauty either way. A few summers ago we got a backhoe out and dug a pit about 4' deep and smoked a whole pig. We created the embers covered the pig in wet banana leaves and then filled in the pit with the dirt we had dug. All day long smoke was seeping from the ground. Most people have no interest in that kind of commitment but you can still get great results more in line with the time frame of a common family BBQ.
In my experience using the smokers with the side heatbox, you can definitely have actively burning wood in the sidebox. In fact you can also grill in the sidebox. Many of them are designed for that. It depends upon how you are using it at that particular moment and for what purpose. I've experimented for example with the heat concentrated in the firebox to the far side of the smoke box and grilling onions in the heatbox while smoking meats. Intending to get some of that onion into the smoke. If you create too much heat the food closest to the firebox can cook rather than smoke. If you have too much wood and a high convection it will even suck the flame into the smoke box. The acrid flavor may be a sign of using the wrong wood such as a softwood. I would also avoid certain hardwoods.
For best results specific to smoking, you want it "low and slow" Most BBQ guys will say something along the lines of the lower the heat the better or just recommend "cold smoking" but there is a technical difference there and I'm not sure that the term is always used correctly. This of course (heat) is also in direct relation to cooking time.
Charcoal: I love cooking with good charcoal. Recently I've setup a weber to work like a smoker. I use a mix of charcoal and oak. I don't presoak but the oak I've been using is decayed and even in our relatively dry summer has pretty good moisture. I lined the bottom of the weber (the grill the charcoal sits on) with aluminum foil to create radiant heat and leave a small opening to create a convection. This works great and you can set it up in a way that will give you lesser or greater heat based upon how much charcoal you use and where you put it. If you are motivated you can create a "snake" to burn the coals in a sort of sequence. The convection is not as strong as in the sidebox smokers and I've had not problems with the ash but I'd consider this more of a hybrid solution and not as easy to extend and manage a long smoke the way you can with a sidebox. OTOH every time I've tried using charcoal in one of the sidebox smokers the convection burns the coal to a white ash and sucks it into the smoke box. I used the weber method a few days ago with burgers and the results were amazing. The burgers came out red. That desired "smoke ring" red but on the outside - thoroughly cooked through. Flavor was amazing. That said I would not do this with say a brisket or even ribs which in my opinion would do much better over several hours on a very low heat high smoke. Brisket maybe 10 hours or more...