Historically accurate vs my own personal tastes...Tough decision
Well, for the accuracies, I can do as you've mentioned, plated knees, elbows, helmet, and the rest chain, as I own a Knight's Hospitaller surcoat.
The rest of the plate would be more of a transitional period where chain was still used to fill the gaps before going almost 100% covered in plate. So I'm just guessing here that it would be late 14th early 15th century? Not sure, but this is where the board experts can help with some of the education.
And yes, pasties! I had a girl come up to me at the same ren faire and she said, "Nice pasties!" and then she proceeded to flip them around playfully. So the slang term has stuck, and I don't think I'll ever be able to call them basagews after that experience.
I would have preferred them not to be fluted but just the plain round discs.
With 14ga, it'll help in terms of protection. I've seen some horror story pictures from my sword play group, where they went out of town and the locals for whatever reason were brutal. One guy came back showing pictures of his helmet downright abused. It was 16ga. he mentioned that some guys were wearing 14ga and even 12ga to help with durability. Not sure I'd like to play in those groups...
As for the center tasset-like bit, I'm pretty confident I'll be removing it in the near future (Saturday morning).
I also have some leather shoe string that I will be using to help tie in and secure the chain mail a little better. The long sleeves are a bit cumbersome.