Are you writing this series as if were originally a book series?
If so, then having the main characters pushed off to a framing device
for the PT would have been really annoying to the readers.

So, how about making the PT a little like the Godfather II?

Before the Dark Times - What if you create an arc for Luke including the completing of his training (as Anakin begins his),
Yoda’s verifying Vader, and Obi-wan trying to get Luke to understand his “point of view”
(which the readers wouldn’t get yet since Anakin is still good and innocent)?
Maybe there is a climax to this arc that makes Yoda and Obi-wan unable to contact Luke anymore
(until the series ends in RotJ).
You could end this story with Luke going to Tatooine for the meeting with Lando and Chewie,
but stopping first at Obi-wan’s home to read his journal and learn the next part of the story.

A Menace Revealed - How about borrowing from the Shadows of the Empire comic that follows Boba Fett
as he delivers Han to Jabba? Since Attack of the Clones reveals the beginning of the Clones,
showing Boba Fett taking on other bouny hunters to claim his prize could be interesting.

Shroud of the Dark Side - This one is the hardest. Need to find a complimentary story with Luke Leia and Chewy
that builds to RotJ but also works in conjunction with RotS.

This way there is a forward momentum through all six books even as you reveal the past.

And it gives you a chance to use your creativity to add your own story elements to the saga!

Just an idea.