There is no hard and fast method , besides experience . 

currently, this is my issue with brrrr.  

It's probably not that much additional overhead, but since we're new to managing remotely I figured it might be best to follow the KISS method as we get started.

(Best done by a BRRRR) Also, rents are coming down slightly and properties are taking way longer to rent out.

Hello, I was wondering if there are any scripts available to craft offers for BRRRR/Fix-n-Flip projects that allow use to back out if the project will cost more/inspection is worse than anticipated, while protecting earnest money.  

Then, with reasonable confidence you can estimate costs.I personally don't love the square foot estimating method for remodeling as I think it is an easy way to lose.

But I feel I see some people grow rather rapidly. wasn't sure if they were using some sort of other method to get ahead. 

A 14-50r plug was always the preferred method, especially before the world woke  up and switched to the Tesla charging standard.

Unless of course, you want to perform a BRRRR strategy in which case you could do that too. 

Great neighborhoods to BRRRR in or find something that has been redone/already turnkey.