Even if you have an absolutely solid home and its worth over 600k, in my area the most you can rent it for is $4000 MAX.

You need to do a cost-benefit analysis to determine if it's worth it.  

Reason being HML's are typically short term loans that are interest only.

The struggle comes when you plan to sell, pay close attention to how the bank would treat the loan in the event you would sell.Even though its a bit more work, banks are typically open to these loans as it provides them with additional collateral in the event of default.  

You won't be able to use conventional financing and must use a non-recourse loan which typically require 40% down.

It may not be worth using an LLC on your first one.As for the calculations, just put the numbers in a spreadsheet and figure out which option costs you more.

As home values rise, so does your net worth.

You'll need something like 125 units netting $200 per door to get there, that's about 10 million worth of multifamily in today's money, so you'll need about 3 million in down payments.

In southern CA, even garage conversion ADU additions are typically costing more than the value added.  

In my experience, a successful BRRRR typically comes down to two main things: finding a good deal and managing an efficient renovation.