Should I bother with a divided merge?

Since the cylinders are already separated by the time they get to the collector, I'm skeptical that keeping them separated for a few more inches before reaching the turbo flange will make a perceptible difference in spool.

Regardless, what I do know for sure is if you don't merge 4 into 1, to prevent boost creep or leaning out the other 2 cylinders when the WG opens, you'll probably need a Wastegate on each pair of tubes, so 2 WG per turbo. 1 WG per turbo seems more simple.