S-04 is fast. Expect it to chew through that 1.095 Stout in 3-4 days tops, at least the bulk of the fermentation. Watch the temps too. That much/fast of a fermentation will create some heat! Let it sit for at least 3 weeks to clean up. You’ll be amazed by how the yeast packs. The high sedimentation is one of its strong points.
Update: A quote for their web site:
A well-known, commercial English ale yeast, selected for its fast fermentation character and its ability to form a very compact sediment at the end of the fermentation, helping to improve beer clarity. This yeast is recommended for the production of a large range of ale beers and is specially well adapted to cask-conditioned ales and fermentation in cylindro-conical tanks. Sedimentation: high. Final gravity: medium.