what would be better for a single wastegate setup, 1-2 and 3-4 runner coming together or 1-4 and 2-3? would it make a difference?

 

1-2, 3-4 would be worse than a undivided manifold, as far as power goes. The goal behind dividing them is to prevent the exhaust event from coinciding with an overlap event.

To make a long story short, there's only two things special a single wastegate on a divided setup should have: a low backpressure dump tube, and for the WG runners to be divided as long as possible (up to the valve if you can).

 

thanks for the reply. the reason i was asking is because there was one that i saw that had a 1-2 3-4 setup. we're on the right track.