We've raised beef for generations. We used to dairy and raised Holstein bull calves for steers. Always butchered about one per year for our own use. Since getting out of dairying 10 yrs ago, we now buy feeder cattle and finish them out. We finish a mix of breeds - Angus, Hereford, Swiss, Holstein, Jersey, you name it! Jersey actually make for really good beef. Very tender and tasty - but the fat is yellowish compared to most other breeds which would tend to turn off some people.
We try to consume our beef so we run out of everything about the same time - burger, steaks, and roasts. Once we miscalculated and ran out of burger about 6 weeks before anything else. First time in my life that I had to purchase ground beef at the grocery store. We bought a 5 lb package and divided it up at home. That was some of the worst tasting burger that I have ever had in my life. Even tried killing the taste by making chili with it and that didn't even work. Ended up throwing the rest out for the cats to eat. Strange thing was - the cheapest crap that Wal Mart had ended up tasting the best (actually, the least awful).
Most certainly, with that size butt, wait til morning to start. I might even wait til 7 am to light the grill.
As others have already said, each butt will vary in time. But smaller butt like yours should be done in plenty of time no matter if it stalls stubbornly or not.
I remove as much as the fat cap as possible and place it down. I think the idea of leaving it on and placing it to the top comes in from brand X grills that dry food out. The Egg is great for retaining moisture so this is not a problem. In my opinion, it takes energy to melt all that fat and that energy could just as well go into cooking your pork. Melting all that fat with the fat cap up can wash a lot of your rub off and into your drip pan too.
Use yellow mustard to glue your rub on. It will not flavor the final product any.
I have the best luck using the lower vent mostly to control temps for low-n-slows. For 250F, the lower vent is only open a crack - about 1/16". I do use the daisy wheel too and those are open about 1/4 of the way or so.
You will find that each cook is different. Vent settings are not always repeatable for the same temps. Differences in weather, humidity, charcoal, etc will change settings. I have found that if we have had rain recently my Egg will require more air to come up to temp. The ceramic will soak up some water and it takes some energy to cook it off.
The trick is to just roll with it and not over-stress. Make small adjustments and enjoy the challenge of finding that sweet spot for current conditions.
I don't recall. All I know is that the research I did on this board back before I pulled the trigger told me to use the Permatex. The cement with the kit is for gluing the gasket onto stove doors. It may not stand up to the weather that an Egg is exposed to. Water, perhaps?