The investor margins on profit are just a little thin.

Reminds me of Dave Ramsey or that Profit First nonsense.Also...

@Timothy Lin  The idea of the 1031 exchange benefit is to allow investors to use the capital gains tax they would otherwise have to pay when selling their investment property, And keep the profit from the deferred tax in their pocket.You get to indefinitely defer it into any type of real estate that that might meet your needs better. 

The trick is to find the most profitable.

Let me explain that better, imagine your rehab is $100k, you would need to do part of the rehab, maybe $10k, and then you can get the funds for those first $10k reimbursed so you can keep progressing with the rehab.Given your experience, I would recommend you start with a moderate or light rehab, mostly cosmetic work so that you can do it yourself and won't get your profit decreased by hiring third parties.

I have done 100% financing, but with borrowers I have significant history and business relationship with, and for a piece of the profit.

Third parties must handle everything, and any profits from renting or selling the property must go back into the SDIRA.

But how do I access the funds or profit of LLC for personals use without "commingle business and personal funds" and what the tax consequence is?

Very profitable How did you find this deal and how did you negotiate it?

The 1% rule and the 35% operational expense rule serve as benchmarks to quickly evaluate the potential profitability of a real estate investment.