It depends on your financial strength, the quality of the property, how many properties you own, etc.I like to start with one significant expense and three months of vacancy.

90% is pretty high.

Your income isn't high enough for it to make sense as a rental and the closer you get to your residence limit the greater pressure you will have to sell it before losing your exclusion in whole or part. 500k right now can make $15k per year income with zero maintenance or tenant risks. 

He uses poorly thought through methods, I've listened to his "methods",  Thus, he has the high amount of  Due On Sale called in a short period of time. 

Lessons learned is not to buy a property with a high HOA.

I would highly recommend you create an LP agreement.

I have sold in California, took the cash and moved out of state (to Indiana) and highly regretted it - I didn't have a real estate investor mindset then.

I can say in Detroit the wholesaler your talking to has most likely found that deal from 2-3 other wholesalers, they literally have to payout 2 - 3 other parties to get the deal and this is what the fees are high and the deal makes no sense.

So that area is based mainly on ease of longer term (ish) rental income, with about 2-3 years stability depending on how often people PCS and the (somewhat) quality of tenants (bc you never know, even with military).

I would highly recommend sticking to the 30 year option or not doing it at all.