How to spread out $100k?

[Adam Draper]

I am new to investing in RE. I have 100K cash that I made doing some high risk investing in the stock market and am trying to spread out my risk. So I started to look into RE.

I have read up on the 2% rule and the 50% rule. I am currently writing a business plan and have really just started my research and have two questions as this point.

1. How much of that 100K can I spend and not over extend myself? How much do I need to hold back for emergencies?

2. I have a current job that does not allow for very much time off. So I am planning on hiring a property manager. I believe that I can purchase 3 different 4 unit apartment complexes for 150K each. At 20% down that makes my initial investment 90K. Those units are currently renting for 450 a month which makes 21600 gross profit per complex. I want passive income and to be very hands off. Does this sound reasonable and should I be able to pay all expenses to include the mortgage and still make 100 per door per month?

Like I said, I am into my research early so any advice would be greatly appreciated. My biggest criteria that I am trying to stick to is maximizing profit and keeping it passive because I have very little time. I am interested in building wealth and hopefully one day be able to live completely off of my RE investments. I would like to make this my full time job within 5 years.

Thanks in advance. Adam