The loan on this house is $1,200,000.I moved in to my new primary residence by the end of the month.Starting July, my original primary residence was available as a rental and was being shown to prospective tenants.My new tenants signed a lease that began a couple weeks after showing, in July.To calculate my primary residence mortgage interest deductions, i'm using the following formula:650,000 / 2 = $325000 loan from January to June1,200,000 / 2 = $600,000 loan from July to December$750,000 limit / (600,000+325000 total loan value)  = 0.81 multiplier(0.81 * $X first house interest) + (0.81 * $Y second house) = total interest payed i can deduct from my primary residencedoes this look correct?

Quote from @Jake Handler: For anyone that has been a buyer or seller of a seller finance property, what method of payment and tracking did you use for buyer to pay seller monthly? 

One of our residents was robbed outside of this property and we ended up paying for the resident to move out and sold this property.

So, questions: (1) How do I properly introduce myself role when calling a seller and cash buyers?  

Need to pay down some leverage to keep that DTI healthy!

My knowledge is free, but I am most happy to charge for it, if someone is willing to pay!  

I take the approach of the investor pays me a fixed fee to learn this on their own so they never have to pay me again if they don't want to.

Choose a designer who understands what attracts high-paying guests and maximizes your revenue.2.

Or does it have to based off a straight paying tenant?

It's worth paying a premium for the brick buildings that were built for multifamily.