It won't be long before you can structure deals more favorable to you.

We decided to transition everything over to a PM software so C could be better handle the accounting and keep tabs on who is past due.

Although i have created a number of systems and tools to help with the rehabs, I'm looking to learn about what others have done in order to expedite the process and handle more volume. 

I have a handy man that handles all the snow, cleaning, Law mow, small repairs, etc..)

Currently I am working full time job and going to school which make it little tricky to balance off but I am sure I can handle it.

One business model I'm looking into is finding a specialist to find the deals, run the numbers, and handle a high volume of purchases and sales per year.

The buyer handles all the maintenance during this period.  

They will handle everything for you.  

How do people generally handle this and/or what % or amount do people use here?

I think the umbrella is a relative bargain (and as you note probably lower risk for insurer as the underlying coverage may handle many claims) for the price (I use  RLI, and maybe your solution is as simple as a lower cost provider)...In my very short time seeing inside of insurance defense, I would see the guys that worked for the major insurers (who fought claims on a daily basis) up their own policies, so that was enough for me..