In addition what percentages do you use for vacancy, repairs, capex, and mgmt (if applicable) and how to tell those percentages are accurate for the property/area the property is located in?

This is accurate. 

@Sean McClure finding a real estate agent to run rental comps is the most accurate way.

There results are very accurate, but of course people change their email addresses and phone numbers. 

If I give you money, what is to stop you from taking off and living the good life in the Bahamas or gambling it away at your favorite casino? 

They are a marketing platform and their data is not very accurate.

If those numbers are accurate that's a great deal.

Understand how to analyze deals, how to calculate ARVs accurately, how to manage contractors, etc..

It costs more up front because the home will have to be appraised again later but this is the most accurate way to know the ARV in my opinion.

I don't want to waste their time because I know that typically there is a small percentage chance on the deal actually working out, but I don't know how else to accurately estimate renovation costs.I have looked at the rehab estimator tool on BP and try to ballpark it but ultimately I know that I will not know everything, and wouldn't want to botch my first deal off of not accurately planning for reno costs.Would appreciate any input - thanks!