One good thing about A Stitch In Time is really that it’s well written and in-character, but as it’s written as direct point-of-view of Garak - and Garak isn’t a reliable source - you can just decide what parts you like to be true and which were just exaggerations, or even simple lies to make the story more interesting.
Because I feel like Garak’s motive isn’t a need to come clean of anything. He might and probably does feel liberated by telling things he probably hasn’t told anyone before, but I still doubt he has any need to stick to the literal truth. To me it feels more of attemt to just keep Bashir’s attention and lure him to maybe pay him a visit (*cough*staywithhimforeverandever*cough*). Telling this version of the story just has a side effect of being therapeutic too.
But that’s why I really like the book, because I don’t feel like I need to treat ity as canon. Ok, most Trek-novels and comic-books and stuff arent considered canon anyway, but you know what I mean. In other books if the focus or point-of-view is on some other, more reliable character I instantly think that there’s no reason for that person to lie and my head just interprets it as canonical continuity.
None of that with Garak. Garak is a wonderful character, you just may have several different headcanons and none of them need to conflict each other. You can one day decide that this is true and another day dismiss it and it doesn’t hurt the character at all.