So for the first move where do your feet start?
As long as you start on your arse and finish at the top without using the ramp, it's a tick.
When me and Ollie Ryall were trying the sitter as a project many years ago we both agreed it would start from matching on the low flake, to encompass the full line.
use your left foot on the good foothold on the RH side of the arete, sounds odd but it made the top bit feel loads steadier for me.
That pics up at the Works, a great shot
I graded the Fin sitter for the harder method, I wasn't aware of the easier way at the time.