It has worked for a long time, but there's nothing sexy about it and you have to wait until you're over the age of 64 (maybe I'm wrong here) to see the benefit of compounded interest investing. 

Looks like you have a solid plan, compound interest will take care of the rest.Can i ask what mortgage product you intend on going with?

Compounding interest will far out earn for you what you could be saving by paying off your mortgage quickly.

Just like anything in life.Once you have made the decision, this is what you want to do.You need to have tunnel vision on your goal.If your saving up for a down payment, work an extra job, side hustle, reduce expenses, whatever.Finding cash flowing properties is not hard to come by, your first property does not need to be perfect or give you the absolute best return; you need to acquire it as soon as possible to start the compounding effect.Hope that helps :) Lets get to work

I want to avoid dipping into my retirement because I’ve run the numbers and even just pulling out $500k for down payments absolutely kills the compound interest and makes a material impact on future net worth.

Money left in the account that isn't needed to regular bills and expenses, remains in the HELOC and compounds the savings benefits.

@Tyler Bilinovic my opinion is to get an accountant earlier in your investment career because your savings compound.

The capital to deploy higher than the Midwest but the margin dollars and compounding is higher.

You are missing the magic of compounding interest.

Leveraging tax benefits like depreciation to scale your portfolio, combined with smart 1031 exchanges, helps you compound your investments.