Quote from @Ben Einspahr: You hit the nail on the head.

I’ve used furnished finder and airbnb to see listings so I can get an idea of rates but vacancy has been a little more difficult to nail down.

Hey @Tim Phillips I think @Jackson Ebersole nailed it.

Bill hit the nail on the head.

The market rent needs to be around $1,800 per side and no more than 2k a month (depending of finshes) I'm having a hard time getting someone to nail down a price on construction cost.

Brock nailed it on the head.

In San Francisco, this choice is taken out of your hands and is instead a determination made from and by the Planning department.From an Investment POV, you are absolutely correct that combining the lower and the ground floor units is the best option to preserve your ability to perform a fast track condo conversion and generate the most equity in the shortest amount of time.

I think you nailed it.

I recommend nailing down your financing plan before going to look for properties.

You will go so much further if you get your fundamentals nailed!