Optimizing that growing dowry/downpayment can be shifting all excess funds to a high-yield money market account, or a CD. 

Not optimal for 'retirement' IMO.So, I would sell my primary, especially if a lot of gain. 

First of all I took a look back at my spending for the past half year to get a good idea of ways I could optimize it.

The key is knowing how to contain expenses and optimize the opportunity.

The savvy DSCR loan borrower will use all the options available to optimize terms, especially in volatile rate environments like today, where every little bit of rate matters in securing profitable investments!

List it for sale and for rent at the same time using your optimal numbers and see which one pans out.  

I would suggest studying everything there is to know about self storage and how to optimize revenue (through podcasts, books, articles online).

The return on equity does not seem like it's optimized.

After all goes well with the build, and your move to the duplex and getting everything rented, then you can sit back and start thinking about how to optimize.

If you're looking to rent, then any optimal tenants would be dissuaded by the surrounding C+ houses.