Careful with swapping seatposts for fit - they should be used to position yourself correctly around the BB, then stems and handlebars swapped for reach adjustments
Partly my point, if a bike fits an inline will work, the seat angle on a surly is pretty slack to start with so pushing yerself away from the bb even more is going against being in a good riding position. Swapped over on my cross check, never been comfier on it.
Inline seatpost is a good call. The bars I have spare are compact and comfy and I quite enjoy doing bar tape, so I think I'll swap them over.