I honestly can't recall the breakdown when I flew often. It seemed around 50/50 or at least in that realm.
In dogfights I could not give any number either. While most of my collsisions are still one sided, I could not say by how much, any number I'd give would be a fuzzy anecdotal thing for sure.
But it's completely different when I attack bombers. When I collide there, it's basically always because of a badly timed high speed slashing attack of mine. In these cases I almost never experience a mutual collision. 'Almost' means I can't even remember when I had a mutual collision the last time - And I always look at those messages.
I'm a Euro player with a much higher ping than the average US player. so I know my 'leash' is much longer. See the picture I posted earlier in this thread, the Mustang who collided on his Front End was me. Look how far I was away from the Jug on his FE.
But let me ask lushe and Wiley this: what would the percentage need to be for a two sided collusion model to be more ideal? Ballpark it I'm not trying to get you to commit to a single digit number.
I don't think I can give a reasonable answer here. I know how it is for me vs bombers, and that I could easily game that. You can't change the underlying physical time difference.