I’ve shopped around with a bunch of different skip tracers and what I’ve landed on for residential is using MLS data (Realist or Remine) or local County data to pull the lists.

you can do it for less. 10k max. there are volume syndication shops you can use. 20k is high for a simple structure. depends on the structure. 

As far as the lender goes, if I'm buying properties that qualify for conventional loans does it really make a difference if I build up a relationship with a specific bank vs just shopping around each time I buy a new property?

The detailed cost segregation study report can help businesses more effectively manage their assets.If assets don’t fall into one of the examples above, there are options such as a 1031 exchange, gifting them through a trust or other advanced tax strategies to avoid depreciation recapture.

I shopped a significant portion of 2 days to obtain coverage at over twice the price. 

If you have time, go visit some of the homes and secret-shop them to see how they compare to yours.I recommend looking at the market at least once a month for the rest of your life to keep an eye on things.

I can't tell you how many times I've gone to the property and it is gone, or you figure out something is wrong, maybe the legal description, or the address, or there is $100,000 worth of junk there you need to haul off that was not in the pictures, or that cool commercial building, that when you get there has the faint words that you can now make out to be a former dry cleaner, or gas stations, or lead smelter, or oil change shop or something like that. 

Any ideas for what to look for in a property management shop that would even take me?

Smaller office or shop buildings might bring in more money but need you to know more about running them.

(Interview them like anyone else and price shop).