As long as you field dress it and get cold as quickly as you can it should be fine to serve medium rare which is best for a back strap. People have different taste so can do what they want but you get the true venison flavor from leaner meat by leaving more juice in it. Also good to add some red wine to the jus and create a sauce or I have even cooked down blueberries with some sugar and herbs to dress it.i have heard that you should cook it "well'ish" , due to bacteria. but i love well done meat.