the most comfy leather saddle that I have used/owned is a Giles Berthoud Aravis (I have this on my Surly LHT) .... comfort from day 1 ... actually it's the most comfy saddle even compared to saddles that are not leather (I've had many) I have my bar height similar to my saddle height

I have a Brooks B15 narrow champion on my daily commuter .... it's fine but not for very long distances.(i.e I would not want to ride 150 miles in one sitting on it)

I'm seriously thinking of getting another Aravis for my daily bike .... not cheap though