OK, so Costco has pre-marinated tri tip right now; I bought one, with the intent of Egging it. We decided tonight was the night.
We don't yet have "hot gloves" for pulling the plate setter halfway through the cook, so we decided that we needed to find a method for cooking direct only. In perusing the threads, we had a Plan. And we wanted the meat done within an hour.
Tri tip was fully defrosted. We filled the kitchen sink with hot water, and placed the refrigerated meat in the sink, while we started up the Egg.
We had decided on a "sear first", with direct heat. So we cranked the Egg up to 500*, and seared the 3.36 lb roast for 3 minutes each side.
We then removed the meat to a pan, and tented it in foil while we brought the temp on the Egg down to 350*. Once the temp was stabilized, the meat went back on. We'd estimated 45 minutes of cooking time, so at 22 minutes, we flipped the meat. I used the thermapen to check temp, and it was registering 116*. Since we have little experience in knowing how fast the meat heats up, we decided that cooking the second side for another 22 minutes was not a good idea. So we set the timer for 10 minutes, and checked again.
I had a little trouble keeping the temp at 350* - it peaked at 400*, and then I was able to get it lowered again. At 10 minutes in on Side 2, the Thermapen registered 131* - so we pulled it.
So the meat was placed in a pan, tented with foil, and left to rest for another 15 minutes. We sliced it open (yes, against the grain!), and found the meat was medium well done - very little pink. DH was disappointed, but we sliced 3 pieces for each of us, and proceeded to dinner - tri tip, grilling beans (with Tabasco and mustard added), and corn.
We pronounced the beef AWESOME. Very juicy, very flavorful, very tender (although the marinade was too salty for our preferences). DH said that if his mom had cooked the meat to this color, it would have been dry and stringy, and she would have poured marinade on it post-cooking, to add "moistness."
We will totally do this again, but try cooking for a total of 30 minutes, instead of 45 as originally intended, and then check the meat temp at that time. The searing worked well - there was a decent (although not epic) crust and char for the meat.
We will also try to get hot gloves, so we can try to cook direct AND indirect for the plan; cooking direct only, without any way to raise the grill, made it more challenging than we expected.