Same as my primary residence - if somebody really wants to break into my house, they're going to find a way regardless of the precautions that I take.

What precautions do you take to prevent unauthorized subletting?

In the past, it was a pretty low risk especially if you manage the property correctly, take certain precautions and even certain property types.  

As additional precaution I use MBAinsurance.net which is one of the only insurance providers that allows you to rent personal LSV vehicles, Mopeds, etc.. to others for income. 

Analysis parlysis regarding all things in life that could happen and how they affect real estate (Buy & Hold) investing Worrying about every single possible thing that can go wrong is different from taking proper precautions for things that are more likely.

What tips and precautions can you provide In order to succeed in this project? 

Hi Aaron,As Nicholas mentioned, there are precautions to be aware of when using high leverage. 10.25% and 9.87% is in range from what I see as HELOCs are ranging in 9's to 10's on average.

Or would be worth pursuing a R-62 Minor Home Improvement License as an extra precaution?

It does seem like it's largely an avoidable issue with some simple precautions.

Additionally for tax purposes, you have to make sure a personal HELOC is not a problem for the accountant on your business LLC taxes (usually not, just a precaution).Rinse and repeat my friend.