I've read both those books, a book about Jim Garrison and a book called Texas Connection, all around two decades ago. Also read Roger Stone's book trying to make the case for LBJ around 10 years ago (last library book I've read, because I sure as heck wasn't giving him money).
You want to talk about opinions and nonsense? They're all full of them, as wells a lot of conjecture, rumor and malarkey. Their is little to no evidence to back any of it up, only bullshirt. (Did you read Posner's Case Closed?)
The Ruby comment is opinion... the opinion Dallas cops, Mob members, girls who worked for him, friends, etc. As in the people who actually knew him! But what does it matter if actual Mafia people laughed at the notion of using him as a hitman? Some guy in a book made it part of the conspiracy, so it must be true. (He was such a prepared hitman, too. Left his dog in his car, did some errands and only showed up like two minutes before Oswald was transferred. And the transfer was way late, so it makes no sense why Ruby wasn't already there, if he was directed to by organized crime.)
I remember reading stories around the time of Snowden ending up in Russia 10 years ago that it was not an uncommon occurrence during Cold War. I remember distinctly reading about two NSA cryptologists who defected around the same time as Oswald. Found this on a Google search:
https://en.wikipedia.org/wiki/Category:American_defectors_to_the_Soviet_Union
Couldn't find any of the articles, but I'm not going to go digging and waste any more time, nor any more time replying to you.
You
want to believe, evidence be damned. Have at it. Ultimately doesn't affect me.