The novel Cobalt Squadron by Elizabeth Wein has the answer, which involves a direct request from none other than Vice-Admiral Holdo herself. Thanks again to Disney Lucasfilm Press for sending me a review copy of the book, from which I get to share background details like these that will enhance your future viewings of both The Force Awakens and The Last Jedi.
Yes, I said The Force Awakens, too. Why, you may ask? Well, the shot from Starkiller Base that destroyed the Hosnian system had physical effects that you could see and feel all the way across the galaxy – more so that what we saw in the movie, and that you could even feel if you were in hyperspace at the time. (So yes, the Resistance transport heading to Takodana in The Force Awakens should have experienced the same thing the Resistance bombers did in Cobalt Squadron.
And … and!!!
Elizabeth Wein, through Vice-Admiral Holdo, reveals exactly how long it was in between the destruction of the Hosnian system and the destruction of Starkiller Base…