Not sure I am understanding this right nor if it is my place to say having the fact I cannot see. But I would just keep all the hair the same length if I was you. Why have a long centre when that will easily grow out with the rest of the hair?
Cut the centre the same and just keep it looking similar in length until the rest is where you want it. In 2 months time the centre will need a trim anyway as it will be too much longer than the rest.
If I have that all wrong, I think this kind of hat could be cool.