Ed agreed, and your incident sounds nasty, good call by the way! I once had a variable guide vane failure too but different and a much more boring story.
While not wanting to get too far off topic, I fly an aircraft with different engines. If it has the CFM56 I fly to N1 readings with no EPR indication. When I fly the V2500 I use EPR. So certainly with the CFMs N1 is the primary indicator of achieving take-off thrust.
Best regards. Tom.