I feel for those who are so stressed out about the poly.  I am more stressed after I have taken it, but during I felt very relaxed.  My key was that what I did in my lifetime I have forgiven myself.  It doesn't bother me those minor things I've done.  I smoked pot in high school and stole from an employer.  I admitted these things to the poly tester and feel I have a better chance of passing by being honest than deceiptfull.  IMOP you can employ all the counter measures you want, but until you truly forgive yourself for your mistakes you will get stressed out.  Try doing this...  be honest, forgive yourself, and don't try to be the person you think they are looking for.  If you are a truly decent person and I think most here are, you have to remember you became that way by the mistakes you made...deal with it! file the mistakes under learning experiences and move on...I wish everyone well...it's been stressfull as hell, but I think it gets multiplied 2x if you cheat.