Welcome. I have an IW 885 and my neighbor has the BGE so we share each other's meals (meats didn't sound right). I enjoy my IW885 and purchased the stainless steel box cover and plate. Makes my cooking better.
The one thing I learn is that I got so use to shutting down the grill with the app. After the app was down, I couldn't figure out how to shut off the grill. This is what happens when I get so reliance on the app.
If you are cooking it at 190-200, then most likely it will take over 20 hours to cook. I did an 11.39 lb at 200 Traeger temp and took me 18 h 30 min. When I am not around like yesterday and the meat reach temp, I use keep warm function until I get home.
You can definitely use the smoker box on the Traeger. I use a combination of both chips and pellets. However, I discovered that using 2 smoke tubes has given me heavier smoke flavor. In my household, everyone is happy with just the flavor we get from the IW885 without the smoke tubes.