My philosophy is, if I already OWN parts, I'll assembly almost anything and see if I can make it work to my satisfaction. If I'm BUYING parts, I'll hold out for stuff that' is designed to work together.
You are talking about some pretty high dollar components. If it was my bike, I'd do whatever it takes to keep it all Campy 10-speed.
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My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.