The computation of the percentage allocation or split is generally done by using square footage, acreage, or some other methodology that is defensible should you be audited. 

If I assemble my own lists from the property appraiser data, it will be infinitely cheaper.

Now if you want real world data points, then think it's still too early as the crowdfunding platforms are all pretty new. 

The county dept. of assessment does not have this data. 

Many agents list undermarket to spur a bidding war.. many props will have 10 to 20 offers on themI just sold a little dinger Yesterday in Salem oregon  4 offers in 24 hours... and thats a starter house 200k which is about as cheap as a renovated home goes for.I sold one Friday in Sacramento it had 3 offers.. and we were able to remove the FHA lender clause and force them to conventional.. so we did not have the flipping time lines to worry about.so its market driven for sure.

I have test driven cars at dealerships without sales people I found the experience to be more enjoyable.

If you look at everything in the neighborhood in your property's square footage/age/condition range that's sold in the last 6-12 months in the neighborhood, as well as every active and pending listing in the neighborhood, you (or a local broker that's competent at analyzing that sort of data) should be able to get a really good idea of what needs to happen to sell your house.

From this data, you can utilize a website bestplaces.net that will give you a breakdown of the percentage of homes that sold, in various price ranges, for a given zip code.

But you should be able to get a lot of data from zillow and such.

And who also knows how to pull zip-code demographics, crime statistics, and other relevant data about a given neighborhood to help you make the best possible investing decision?