If you want to do long term, then you need to ditch the rehab costs initially and plan on coming up with those through another financing methods or cash, once you own the property. 

The ADU is 25% of the property using the sq ft method.

Should I sell for the gain and go into another renovation or is there another method that would help build cash more efficiently?

What are some suggest processes\methods to remove all bills paid and implement RUBS? 

You and/or your accountant might determine that you do have some earned income based on your active management, rehab or repair, or method of renting the properties.

If you are using your HELOC for a downpayment, your rent needs to cover the cost of your new mortgage, HELOC and expenses.I'm analizing a lot of deals now; must have looked at close to 100 over the course of the last week and this method makes it tough to find a property that makes sense numbers wise, however there have been quite a few that have been break-even given this scenario so i know there will eventually be one that provides some cash flow, even when using a HELOC, i just have to find them.Good luck!

You find the list, track down the person by skip tracing or some other method. 

Hello Matt,In the institutional investor world the method used to manage turn cost was $ per sqft. 

The biggest benefit to this method is you get to keep your incredibly low primary residence interest rate of probably 4.25%. 

I know that doesn't take into account the finish/quality of the homes, but is that method generally accurate?