Here's a funny thing. I beat the ever loving crap out of my car, enough to the point that I killed 5 built transmissions in one summer.(I'm not proud..gotta either laugh or cry..I'll take laughin and drinkin). Someone my flex never broke.
I did however have a redrilled one from when I had the trans done the first time (to use a 245mm converter) and the holes were a little egged. Upon doing my cam, the flex had been off and when I hand started the bolts, I was 180* off.
Yeah, I pulled the motor to rotate the flex.
From here
To here
You can get away with not unhooking things 100% and not pulling things apart fully. I didn't take anything off the motor, I do when I pull one, but not to lift it for a min.