RE: Mathews Switchback
Ditto on what Dalejbrass posted. The shop should be responsible for setting the peep properly. At least that's what we do and it is included in the purchase price of the bow.
Some shops, however, knock the purchase price way down and then charge extra for each and every item. You should have a talk with your shop as to which way he/she works it.
In any event, a bow press is really what's needed to do the job right.
Enjoy your new Switchback. I was able to shoot one last week and it is a very smooth drawing and nice bow to shoot.