stock ls flex plate, stock dodge ram 1500 converter, i now use a 1" thick adapter to mate the 2. and I use 2 half inch thick plates to mate the tranny to the motor, one plate has the chevy pattern, the other has the tranny pattern. i mount the motor plate to the motor with counter sunk bolts then mount the tranny plate to that with counter sunk bolts. the tranny then bolts to that. hope that makes sense?
if you are interested I will share the schematics and source code, for reference only of course :)