There are some very impressive people/projects that are willing to use IRA money you just need to look and never be shy about requiring/requesting and exhaustive history of how well they've done.As a borrower, my self-directed investors a slightly more expensive than institutional money for construction, but infinitely less headaches. 

I have come slightly close to getting out all of my initial investment in the short term but I have not gotten out all of my investment (purchase + rehab) out due to 1) typically we do not get 80% LTV (we typically get 70% LTV) 2) the refi appraisals come in below market value (common issue in san Diego).Therefore I have yet to achieve the infinite return in the short term. 

The idea is to use OPM for infinite return and to grow rapidly

In fact some of the older panels are deemed obsolete & should be replaced, especially if you see surface rust on the bottom shelf of the panel.Here's a pic showing busbar corrosion on the one I replaced due to years of basement humidity/moisture.Good luck....

Keep in mind that the initial investment is often $0 when leasing so returns are infinite, it’s akin to getting a property with 100% financing and negligible mortgage payments.

In an ideal situation, a BRRRR should yield infinite return because you would have none of your original invested cash in the property.

I suppose I could still pull out the rest of my money giving me an infinite CoC return but I had just assumed to leave about 40% equity in the property in an effort to be conservative.

Because I have no money down, any cash flow generated would result in an infinite ROI.

You could obviously use the HELOC, or borrow the down from your 401k, you could save cash for a down payment and get standalone financing for the new buy, or any number of things.There's plenty of SFR near you that would cost less then 165k, and I'd be tempted to use just as much equity as I needed to put a down on the first one and get it rolling before repeating the process.I wondered if you'd ever heard of the Infinite Banking Concept?

Based on the latter approach, you can essence acquire an infinite number of properties.