You'll increase in speed as you get better managing your properties, setting rent rates, finding deals and learning the systems. 

We have increased rents on about 8 units now by over $200/mo each by turning 1 and 2 bedrooms into 3 bedrooms.

Because of the prohibited transaction rules, doing so could be a violation of the rules, or at the very least, would limit your flexibility with the investment and increase the chances of a prohibited transaction occurring after the investment is made.Here are some alternatives to commingling the assets: using the Solo participant loan feature to do the deal outside of retirement funds using non-recourse financing from a lender or private source in combination with retirement funds as the down paymentusing a 401k or IRA and partnering with non-disqualified persons

.- Yes, there is increased liability; however, if you take earning your license seriously, it doesn't take much to understand what must be disclosed, how to disclose it, etc.

I have a self-directed 401K (solo 401k), and purchasing real estate for buy and hold.However, I would like to grow it by taking after tax dollars (W2) and issuing myself a promissory note of 50K but instead of doing “minimum” payments of prime + 1%, could I artificially increase it to say prime + 5%?

Because of the prohibited transaction rules, doing so could be a violation of the rules, or at the very least, would limit your flexibility with the investment and increase the chances of a prohibited transaction occurring after the investment is made.

If they do this correctly they can do it with multiple properties and keep increasing their wealth.  

The lease is month-to-month.I’m looking for a recommendation on how to increase the rent.

Inherited tenants increase risk, as they were not screened by you.

Zillow estimates an 11% increase in home value.