This can put a significant strain on your finances and cash flowThey also often require a large down payment themselves and may have a strict repayment schedule that can be difficult to meet, especially if there are unforeseen circumstances or delays in renting the property or generating income from itIn addition, relying on this type of loan may expose you to higher financial stress and the possibility of default if you are unable to meet your loan obligationsThe final decision depends on your overall financial situation, risk tolerance, and your ability to manage the associated costs and obligations

I have done this, and it has been a great decision.

Is this a wise decision to use a HELOC on property number one that only has 20 to 25% equity in it to fund a down payment for a live in house hack in multifamily property number two?

Again, the BiggerPockets store has some books on this topic, or you can learn about it by watching podcasts, reading blogs, and interacting on the forum.

It might be a better decision to do a 75% Cashout Refinance.

Then make the decision if being a hands on landlord is something you are realistically interested in. 

Quote from @Sean O'Keefe: @Ignacio Vidal Traver This thread also has a great hours tracker / activity log https://www.biggerpockets.com/forums/51/topics/816680-real-e...Sure, sent! 

Search a little..https://www.biggerpockets.com/forums/70/topics/291046-ppr-note-fund

Hi @Joseph Goode I didn't see any responses on this so I wanted to see if anyone did get back to you via PM as I am interested in this topic as well.   

While this insight is valuable, it’s important to remember that thorough analysis is always crucial before making any final decisions.