I'm exactly in the same situiation as yours!!

Even our PD is similar. I'm thinking to change to part-time now so that I'll have 5 more months in part-time H1 to look for a post-doc. I'll need to do amendment on my H1.
My lawyer told me that it's dangerous for my I-485 if I don't have a full-time job. But ChenDanHong said since I'm in NIW category, I might be OK without a job.
Good luck to both of us!