Please note the information provided below is a layman's definition designed to provide a basic understanding for the general audience.

Your property manager's comfort zone apparently doesn't extend to the larger project you'd like them to take on.

As a first-time landlord, I'd feel comfortable renting this out knowing that it will not need heavy repairs and know the area wellWhy renting will not make sense:1.

@Joey Harris,The 1031 is designed to allow you to indefinitely defer paying tax on profit and depreciation recapture (a big big deal over time).  

Given the numbers and assuming you can comfortably manage the property or hire a property manager, I would lean towards keeping the duplex.

In this case, we're still within what I feel is a comfortable range."

Last time I checked, there were hundreds of spreadsheets and I'm sure many of them are designed by/for flippers. https://www.biggerpockets.com/filesYou can always find fileplace at the bottom of every screen, left menu.I also recommend you go to etsy.com and search for "house flipping spreadsheet."

At the end, it's whatever you feel comfortable with. 

Here’s how you can calculate the income requirement:Monthly Rent: $1,680Income Requirement Calculation:Multiply the monthly rent by 3 to find the minimum monthly income required:1,680×3=5,040Therefore, a tenant should ideally have a monthly income of at least $5,040 to comfortably afford a rent of $1,680 per month in the DFW area.

I was just trying to see if there was anything on the market thats simple to plug and play especially with offer templates designed and already integrated to send out as blind offers.For lead gen I do run an agency so generating buyer leads wont be an issue.