Either computer will be fine.. whatever is ready to go.

saddle bag: 2 tubes, 2 levers, 1 bike tool, 1 patch kit, 1 tire boot, 1 GU packet. mini pump on the frame. keys, cell phone, snacks in jersey pockets. over 30mi =2 bottles. over 60mi 2 bottles + extra drink powder in a ziplock to mix more.