Can someone explain how the wildcard and unused portion of homestead exemptions work?

My wife and I will be filing under Chapter 7 and our state (PA) allows us the choice of the very meager PA exemptions or the more generous ones from the Feds. We will go with the Feds, but we're unclear with a couple points. First off, our assets include a home with no equity. We have two vehicles, combined fair market value of nearly $6500. The joint vehicle exemption would pretty much knock that out. Our household goods would also be exempt. (We don't have that much, maybe $8000 if we had a yard sale!) What we are not clear on is the section that talks about wildcard exemption and unused portion of homestead. The UPH exemption is $10200, I think, and it says it can be used on any other property. We have a stock savings plan of $6000. Can the wildcard or UPH exemptions be used on the 6K?