Job Market paper: what are the criteria?
I agree with @AlexanderWoo--ask people in the field that you know.  However, this also seems like a situation in which it might be useful to construct a new paper that combines material from the first and second paper.  Don't make it too long, though, and get people in your field to give you feedback before sending it, if possible.  

You also might want to use different papers for different applications.  Think of this as a an addendum to the answer you referenced.  If you're applying for a postdoc, is it a postdoc with someone who is working on similarly technical material, with a lot in common with your research?  Or are they hiring a postdoc because they lack expertise in your area and need someone in that area as a collaborator?  If you think that the people likely to evaluate your application are capable of understanding paper 2 on its own, then maybe you should send it.  If not, maybe it would be better to send paper 1, or the hybrid paper I suggested.