One of the few benefits of SIP is being able to smoke more often.
I guess there is something to be said for having my old Jr.
I second the vacuuming suggestion. I also have kiln bricks and the thermal mass helps stabilize the temperature swings.
When's the last time you cleaned it out? I've had mine go out twice, when on smoke mode. I vacuum it out and it's fine.
I'm wondering if I need a new igniter. Thoughts?
As noted, very doable. Placement matters. The butt will take longer, so put it where it won't require moving to get to your ribs.
With my Jr, I can do 2 butts in back and still squeeze in 1 rack in front. You will lose heat removing your ribs. I've added firebricks and the added thermal mass...
I don't have your issues on my Jr. I've had much more consistent results since I put firebricks around burner to increase the thermal mass.
Having something to hold the heat might help you increase it. I bought mine at Ace Hardware, but I may get more at the local ceramic store.