I am very jealous that I missed that! If it's your size, it's probably my size too...

I think the open jacket option would still be at a black-tie level of formality, just a little less formal than it would be done up with a belt on top. I think it would look quite nice worn open with a contrasting waistcoat underneath.

Since it seems like it would be strictly black tie, I wouldn't wear it with a long tie, but all the other options you listed sound like they'd look fantastic.

I also much prefer it with a belt over the top, though that can lead to wrinkles if the fit isn't just right.

Congratulations on a really great find! I'm looking forward to pictures!