Here is the first time I fired up my newly finished Mini WSM. Went for about 5 hours strong at 225. I removed the lid once at 3 hours and it took about 10 minutes to come back to temp. At the 5 hour mark I had to knock the ash off the coals. The temp came back up really quickly and leveled at 230 until I shut it down at 7 hours.
When it was running at 230 the top of the dome was about 260.