A good rule of thumb is to take your calculation and add another 10%.  

This should be very easy for you with your engineering training.

Live, work, and play in Des Moines which makes it relatively easy to keep a finger on the steady city pulse.   

Do you have a full knowledge of the RTA and how the LTB both interprets and makes rulings based on it. 

The following covers the self-employment rules. https://www.irs.gov/businesses/small-businesses-self-employed/self-employed-individuals-tax-center

We have several doors we rent out by advertising on kijiji, and they go fast (couple days and were screening 5-10 app easy)  wish we had many more to rent out. 

We have made numerous offers following conservative guidelines (BP calculators, 1%, 70% rules, etc) and have not had our offers taken seriously.

these homes are traded more like commercial properties.. once they become rentals they pretty much stay that way the rest of their lives... so the resale value is totally related to the gross rents.. as each investor gets taught the 2% rule or 1% rule etc etc..

At that time, I wanted to be a lawyer, and I felt that I didn't want to work long years and work for someone who would take the easy way out from my back.

Solo 401k plans are no different then full-time employer plans in that they are both sponsored by a business; however, the IRS created solo 401k plans to even the playing between big company employer plans  by relaxing the rules for self-employed businesses to be able to qualify for solo 401k plans (see IRS Pub. 560 which list the requirements to qualify for a self-employed 401k).