[El Ropo]

My experiences say for low and slow you need a diverter / diffuser

You haven't mastered temp control in a UDS yet.

Also, you need to shut things down on the way up, prior to target temp

I wholeheartedly agree with this, it's much better to catch temps on the way up.

Knowing you will need to open to add meat, mop, sauce, flip, etc. That gulp of air is going to fire things up

As a beginner on a UDS, I'd skip all the extra steps (voodoo) which IMO are totally unnecessary. Concentrate on fire management, and knowing when to pull the meat off when it's "done". Leave the cooker closed, don't peek, mop, spritz, open for pics.

If you insist on doing any of this, a great way to keep temps stable is to close down all intakes 5-10 minutes before removing lid, do your voodoo ASAP, then after replacing lid, leave intakes closed for another 5 minutes, then open up the one intake to the previous setting of 1/2 open or whatever it was before the voodoo. Nope, not joking.

I would venture to guess all of us have burned up some meat while we were learning the ropes

I learned fire management on my modded brinkmann gourmet, which is basically a mini UDS. So by the time I did my first cook on the UDS, I had all aspects of fire management down. Never burned anything on the UDS. Destroyed some chicken on the COS offset before selling it on CL though. Creosote from heck and rubber skin.