Building a long term buy and hold strategy

[Jake Smith]

Hello BP,

Im looking for ideas and input on building my long term buy and hold strategy, 

My goal is 500,000 per year net cashflow in ten - fifteen years through long term buy and hold rentals with a medium risk tolerance.

I just turned thirty so time is on my side.

I currently have six doors, total net cashflow with the six doors is 3000 per month. 

If it helps, my total net income per year is about 120,000.

I have 175,000 dollars liquid that Im trying to decide what to do with, my long term goal is getting out of SFH and into multifamily properties to scale faster.

I love the day to day of the real estate business so I don't want to give it to a syndicator or be a hard money lender.

What would be the most efficient use of the 175,000 to get to my goal?

Would you use 125,000 of it as down-payments on five-six single family homes to immediately increase monthly cashflow, or would you hold it and wait until you had 250-300k to invest into multifamily properties? 

Ive looked into other "what would you do with..." posts and haven't seen this specific question asked.

I really appreciate all feedback and ideas, thank you in advance.