Sometimes you just have to wrestle with the prick of a thing
You don't have a dowel in the block and a dowel in the bell hitting against each other?
Are you sure its a 20V flywheel? and not a 4AGZE flywheel.
What's the diameter?
200mm 16V
212mm 20V
225mm GZE
How did you "ensure" the clutch plate was lined up? Do you have a dummy shaft?
How tight did you do up the pressure plate? did you torque wrench, or just F/Off tight with spanner/socket?