Not the way I am thinking of it. A retro is more what went wrong / right with our interactions in the team or outside team. It's rarely in my experience a technical what if discussion

I am thinking more a way of allowing a single CTO to engage regularly with individuals, less time consuming than 1:1, more free flowing and technically focused - a discussion on what are good or bad or crazy approaches.

Again the main things not to do are give the answers nor set deadlines. That's for the team / coders to do.

I think I see a blog post sized comment coming so will stop now :-)