Metrics for tumblr

Hi guys,

Recently I've been trying to get some decent tumblr expired accounts with high PA. But what i am confused with is - is this the only metric to look at when getting expired tumblrs? Should i also pay attention to TF and backlinks? Thanks!

Focus on PA which must be 28 to 30+ then PR, TF is also OK but its hard to find the expired tumblrs specially TF based.

Thank you very much!