Dan, this might be one of my favourite threads on the entire forum. There is something genuinely lovely about a 13 year update that ends in a four piece collection and a wife who probably rolls her eyes every time the IWC bag comes through the door.
The Petronas and the Lake Tahoe sitting next to each other is a fantastic pairing, two very different moods in the same Pilot family. And the Ingenieur 328901 has aged into one of the most quietly respected pieces in the current lineup, I think people will look back at this generation the way they look at the older Genta references now.
What I like most about your story is that you did exactly what most of us pretend we will do but rarely manage. You started with one proper watch, lived with it, and let the collection build naturally over more than a decade rather than panic buying three pieces in the first year. The collection has a real personality because of that.
On the gold obsidian Portugieser on rubber, go for it. That combination of warm case metal against the deep dial on a sporty strap is the kind of contrast IWC does better than almost anyone right now. It will sit beautifully next to what you already have, especially photographed alongside the Petronas.
And Tilo answering on both ends of a 13 year arc is exactly the kind of thing that makes this forum what it is. Welcome back properly, Dan, and please do keep the updates coming. Curious to see where the collection sits in 2038.