These are great questions you are asking, and while I am learning right alongside you I will offer this: it's less about determining the perfect rate now because your experience will help you determine what rate it right for you and your market, and more about you understanding and meeting the needs of your clients (owners who are interested in vacation rental management). 

While it is not prohibited to invest alongside your IRA or solo 401k for that matter, specific rules apply so it is important to consult with your tax professional before proceeding. 

I had run into hiccups of education gaps and uncertainty and your post gives so good avenues to explore.You may have noticed but I have joined the millionare possibilities, okc entrepreneur group and real estate investing group on meetup.comI also am planning on attending the failing forward presentation.

Will real estate agents adopt a new product to sell along side traditional houses?

Looking to ramp up and do more alongside growing my brokerage.

I've had to do a lot of the work along side these managers to get things right when I shouldn't have to.

I have done commercial and residential loans since then with minor hiccups. 

I'm trying it with Turnkey but... we started off with a few hiccups. 

One hiccup and you will run short of time .

So even if the return on your notes is 10%, its impossible to get 10% on the entire amount of cash you have to invest.And, you are correct that you must have reserves to deal with hiccups like foreclosures.When I first started doing this I made direct loans via a broker.