Opening in the round

[Linster]

This is a continuation of my previous post questioning how to convert a pattern to the round. I'm working from the waist up on this garment and there is a 9 in. vertical opening in the middle of the front neckline. My question is what do I do when I get to the part where I need to split the pattern? I'm not sure if it's a good idea to start knitting back and forth before completing an entire row in the rou