I did have the Journe Chronometre Souverain on my mind for awhile... (see 4 posts down) but after todays test drive of a new friend's CS which was just traded for something really cool, I realise its not a watch i would consider personally.
In terms of 38mm vs 40mm on the Journes, my take is the 38mm is what he came out with originally and it all comes together perfectly and is proportionate and super comfy, especially for the Octas in 38mm. the 40mm is just giving into the demands of the guys wanting bigger watches which is/was the trend the past few years. no difference to the movement just supersize the case which to me makes for worse off watches, this confirmed after i had a chance to check out a 40mm CS.
hope you enjoyed the short review and showdown :) cheers, raph