Beef Strip Loin Dilemma

Keyrock

Need some help. A friend gets packer briskets from "a guy" a couple of times a year. He gives them to me and we have a bunch of guys over (usually 10-15) for a big lunch. Last week he said he was getting another one, so we planned to have our big lunch this Friday. He dropped it off with me on Tuesday and it turned out not to be a brisket but a 20 lb beef strip loin (I think. It had no label on it - see picture).

I've never tried to cook anything like this. I don't have the grill capacity to cut it into steaks (New York strips?). Just my large Egg. I'm considering roasting it at around 250 and doing a reverse sear at the end (seems popular on YouTube). Just wondering what other methods I might want to consider. Also, it definitely won't fit on the Egg in its current state. I'm considering doing half in a roaster and possibly doing a reverse sear on the Egg after the other half is done. 

Appreciate any tips on prep and on sides and sauces. Thanks.

Keyrock

Sorry for the double post. I thought I had accidentally deleted my original one.