Without knowing your load or facility with changing tubes I'd start off with the assumption that the front tire wears at least twice as long as the rear and gets 1/3 the flats. After that differences in road feel are felt through the hands/front more than the seat/rear. So if you want nutso puncture and wear resistance take care of the rear tire first then put a nice supple tire on the front. I'd be more inclined to put a Schwalbe Mondial on the rear than a Marathon Plus on the rear. How much weight is on the wheels?