However in some areas I would also use a year built filter was well. 

Instead of you talking to everyone let your mail piece filter for you and drop out the motivated seller. - Once I determine how many to send out a week, can that be automated?

Searched my county then filtered out of state owners with high equity or you can do a quick list and right the absentee owners then use your desired filters.

And frankly filtering isnt a bad thing and a voicemail does just that.

Or put in a Hepa filter machine in there for a few days and see if that can get rid of it? 

What are other parameters that I should filter my list to so I dive deeper to find those hidden gems?

If you get too many calls, your marketing is too broad and must be filtered to only attract motivated sellers and REPELL the others.

Metroscan will return beds baths size SFR kind of stuff however if you want equity filters then you'll use listsource online and do the same thing.

You can simply address it to "Property Owner".However, if you're trying to do a more personalized mailing...like a yellow letter, you're going to want to personalize the letters.Also, if this list provider doesn't give you the property owner's name, I'm guessing you aren't being provided a large number of filtering tools either, so you're probably not targeting a specific subset of owners. 

A lot of people don't follow through on anything, so I've learned to filter motivation and abilities a bit.