I just back from the store where they had a 12lb sirloin tip roast on sale for 2.68 a lb. Got it home, trimmed and washed it, put on mustard and loaded it with Montreal Steak Seasoning. There is a few layers of sinew/fat that run through the meat. My question is what temp is best to take this too? I am looking to slice it into 1/2 in steaks and serve with some au jus for supper tonight. Is a piece of meat like this best to take to around 140 or is the 180 better to render some of that fat.