My guess is that perhaps nothing can be said for time scales of vehicles moving at different velocities to be proportional to each other on a percent scale of total time elapsed..... only that the end results at the end of 20 years accumulate to the proportions that they are......
and so it cannot be determined in absolute time what percentage of clock ticks occurred before the U-turn of Ship #1, the De-acceleration of Ship #2.... none of the above.... if this isn;t true what I'm saying here..... then I can't think of another answer
On another note, is it written down anywhere that this is true?
Given Obect #1 Is traveling with Respect to the Earth at Lorentz Factor X
And Object #2 Is Traveling with Respect to Object #1 at Lorentz Factor X
Then Object #2 is Traveling with Respect to the Earth at Lorentz Factor 2*(x-squared) -1
I discovered this, I wonder if it is written anywhere or can I get credit for this equality.
You can test it out and you'll see I'm correct.