using all wood?

When I had my cheapo offset I had a firebox to go on the side.
The smoke taste is more prevalent, but it's not overpowering as long as you're building the fire right. You want a small fire, and you can go about adding fuel in a couple of different ways.

One way is to have a separate wood fire going and just adding the coals in from that fire with a wood stove shovel (or whatever that won't melt or burn you) whenever you need in order to maintain temps.
The other way (which is the one I used because it was easier for me) was to lay the splits on top of the fire box ahead of time. That preheats the splits, and burns off a lot of the 'bad smoke' flavor that you'd get from throwing cold logs directly into the fire. Sometimes they'd ignite on the pit, but as my practice with it grew I got better about knowing when I'd need more fuel based upon wind, outside temps, and time passed.

When using an offset I recommend using wood the entire time. When I first got my C.O.S. I used charcoal, but frankly it just got too damn expensive to run it that way. The biggest reason for this is because it's not designed to run this way. Wood is cheaper when considering the amount of charcoal needed to be added and used to heat something up that large. There's a reason practically every cooker designed to use briquettes is vertical.

As far as starting the fire initially you can use briquettes, but a lot of people prefer using lump charcoal. I never noticed much of a difference truth be told. I just used a little bit of Kingsford Blue to get the first few splits started up and went from there.

I start the fire in the SFB with 1 1/2 chimneys of lump charcoal, leave the vent wide open, close the SFB door and place a split on top of the fire box to heat up. Once the cook chamber is up to or a bit beyond my desired cook temp(usually about 300°) I put the food on and add the first split. The heated wood will flame more quickly than an unheated one, you want to have flame, a small hot fire, to cook with.
I use splits about 9-10 inches long by 2-3 inches thick in my CharGriller.
This photo was taken in the winter when I often put the next split for the fire in the SFB to heat up, in warmer weather the wood stays on top.

I also got my start on a Duo and glad I did. Taught me a lot of fire management. I have since moved up to a huge Horizon smoker but loved my Duo.

For sure get the firebox. I use a small amount of charcoal with wood to build a good base, then go with all wood the rest of the way. I also do what clffcarter does and warm the wood on top of the firebox, ignites right away. Smoke flavor will not be overwhelming if you run a clean fire. You shouldn't have smoke billowing out of the smoke stack. Should be fairly clear. I always run my pit with the firebox vent wide open as well at the smoke stack. Heck, if I'm getting too much smoke, I'll run the pit with the firebox door wide open till it's chugging along.

Good luck !