To give you some reassurance, take a look at the last page of this pdf. It shows where JE removes material from their forgings to lighten the piston. You can easily remove it from under the crown and around the pin boss where it's REALLY fat.
http://www.jepistons.com/PDFs/TechCorner/SCPDrawings/JE_Piston_terminology_and_features.pdf
I did this on a set of 3.3L turbo pistons and it was surprising how much material was removed to get the weight I needed out of it.