Yes, combine as close to the antenna as possible. The lengths of cable must be *exact*. And I mean really exact, not just close. However as suggested try one antenna by itself to see if there's any actual improvement with that. (Also to others: is it normal for an 8-bay to be shipped working like two separate 4-bays?)

From the directions everything's coming from, you very well may require a rotor. It should also be noted that an 8-bay is going to be more directional than a 4-bay, which isn't going to help with your current situation. Buffalo and Toronto are much closer together where I am in Markham, and even then I still find I need to be fairly exact on my aiming for some channels, especially distance ones. I know back when 49 was broadcasting at low power on 34, I literally had a 3 degree reception window.

Height is very important. 10 feet off the ground may not be good enough.

You may also find that your reception improves as we get into colder weather; my best reception of distant Buffalo stations is best in winter time.