I just got done reading a bunch of those sites.   Had me going for a while, to be honest.  

2 holes:    
1.   How would time travel to a similar dimension change anything about the time paradoxes?    If he's here, it's safe to say a virtually identical copy of him landed in his own timeline.  

2.   Common misconception about the idea of similar dimensions where certain world events vary:    You forget genetics and the mechanics of birth.    If your parents had sex on a different day, or any number of factors,  a different sperm and egg could have combined leading to a different child being born than you.

His theory about millions of worlds with radically different versions of you on them having actually been observed by travelers is improbable.    Odds are most of those worlds wouldn't have a version of you in them at all.

A 2% difference between worlds in 1975 would lead to a much much more massive difference by 2036, because so many things are so totally butterfly effect intensive.