I work in California, and you will never see the 2% rule in effect, unless you're down there right near Mexico.

He rejected this, effectively calling me a slimeball for refusing to pay him the $750 outright.Am I out of line here?

If you want to test the effectiveness, buy another domain and put that on the side.  

Manage your property effectively, be especially careful in the area of safety, use common sense, and have a lot of liability insurance.

The only way, in my opinion,  to properly orchestrate a wholesale as an agent is to list, agree to commission or fee, and then have the contract assignable.

The following was found in a google search:When septic systems are properly designed, constructed, and maintained, they effectively reduce or eliminate most human health or environmental threats posed by pollutants in household wastewater.

I'm struggling in finding resources on how to effectively and accurately calculate the value of property as well as AVR.

The latter option would save you the out of pocket expense while effectively financing the cost over the period of the loan.  

IMO, it takes a certain personality type to be effective as a property manager on a larger scale.

If you lack knowledge of how your actions effect others you may never see the unintended hardships caused by what you do.