Ok, hive mind - need some suggestions. Bought a giant beef tenderloin from Costco (the de-veined/de-fatted version). Before any research... my initial thought was to salt & pepper, sear on high on the BBQ for 3 minitues/side and then 30 mins in the oven at 350 in a cast iron casserole. I am thinking that would give me medium/medium-rare when I cut it after. Yes, no, maybe?

Thanks in advance.