As far as I am aware, the aft main tank pumps should produce pressure almost down to empty, so you would still be in a situation where you had just under 30 minutes to dry tanks- a GO around to 1500' should not use a great deal. Actual unuseable fuel should be quite small, after all that is the aim of design! Carrying out the Low Fuel procedure should ensure you crash without asymmetric power (that's a joke!). I would have confidence that you could GA with 1200 and fly a circuit, though I might insist it was a short one!
I did Amber 760 recently. Not especially desirable, but at $150 a barrel, we are no longer tankers when not economical.