I torque the flex plate to the crank at 55 lbs. The bolt i have for them use 11/16 sockets and the flex plate to torque converter bolts are 1/2 socket. This the first time for me are the torque specs 55lbs for the flex to crank or more.
The factory service manual says 55 ft. lbs. That's what I use and haven't had any problems. If it takes a 1/2" wrench on the torque converter bolts their 5/16" so 22.5 lbs. is right. I also use some loctite on the bolts to make sure they don't vibrate loose.