@nexchap thanks for spelling out the gain calculation in greater detail, big help. The second method may be less intuitive but it's simpler to follow because it's an easy sum of three boxes on the sales schedule.
In my case the K-1 sales schedule had a blank for the sales proceeds so all I have to go on is the amount on the 1099. For basis, the K-1 did my work for me by including a box 9 "Total Adjusted Basis for Capital Gain/Loss Purposes" which is the sum of the initial basis, adjustments to basis and ordinary gain. So I can put that as the basis on my TurboTax 1099-B.
