You could shape the posts to have 5 sides to simplify post to beam joinery.
The ring of plates is in tension from the rafters pushing down and out, so you should consider that.
Lowering the ties to run plate to plate could help with that.
Lastly, because there are so many rafters converging to one point, you could put short (purlin) headers between the hips about 1/3 from the top, and have the common rafters butt to that. Otherwise, no matter how accurate the cuts, something ends up wonky at the peak. The headers give you a little bit of flexibility.