So you reckon H2S only shows on EOV 7? It's the same oilfield as the Marathon Well and other EOV's well so the content should have been quite predictable and the expected capacity and characteristics especially where there was previous oil to go on?
Would you wait until oil was flowing then to order an FPSO? That would be a 2-4 waiting period.
H2S may be the same but the methods of treating it are far cheaper and less problematically.
I posted some links not too long ago on another thread, showing the cost of H2S treatment has fallen, with links to companies with specific skills in that respect.