I also build specs(actually my MONEY builds them) to keep the juices flowing in Texas and Utah and have posted several threads here on bigger pockets with the results.

Getting belly to belly with people who know other people? 

Like my dad always said RE is a Belly to Belly business...

Once folks realize this is a belly to belly business their close ratios go way up... now of course if the sellers are out of area or out of state then you MUST give good phone to be successful and that is another discipline you must learn.. you must be very good.

MTR and STR can juice cash flow, but they can also juice headaches.

You always run the risk of running afoul of a "prohibited transaction", you have to maintain % contribution into perpetuity.....Again not to say you can't partner with your IRA, and I would probably do it again...just make sure the juice is worth the squeeze on it because it's a whole nother bag of worms to deal with.

The reason this failed miserably in Chicago is because the project went belly up. - The money is not cheap and the debt will not be subordinated.

Flipping is a self-employed job with high risk and high transaction costs.By the time taxes and agents are done with you, the juice is rarely worth the squeeze.   

The smaller platforms will probably account for only a fraction of overall bookings, so the juice may not be worth the squeeze. 

I suspect Oakland does not have the juice to enforce this.