How much pressure should you apply to a pre-forclosure?

[Nick NA]

Need some advice on how to apply pressure and not seem to eager at the same time - 

I contacted the homeowner of a bank pre-forclosure that he had inherited from a parent.  He and his brother were going to renovate and flip the house but have not gotten around to it in the last few years and now are just waiting for the bank to take it off their hands.  I got permission to walk the property, it currently has a tree that has fallen on the roof which is leading to mold and water damage(no big deal!).  After the walk around I told him I was interested still and wanted access to the interior. Radio silence for almost a week now. 

I would like to get the property for what the bank note is, which he originally said he would be amenable to, but now I'm concerned the more I push the more he is going to push the price up.  Do I wait another week to pester him more?  Offer 500-1k to get the deal moving? Wait and see how it goes at auction? Anyone have any experience buying notes off of credit unions?

Thanks for any feedback