On bikes where my body position is essentially the same (road, touring, etc) I have the same saddle. The saddle I feel most comfortable with on an MTB is different because my body position is slightly different. MTB rides are shorter in duration and I also tend to spend more time off the saddle when riding MTB, so my tolerance and comfort is a little more forgiving. Touring demands a comfortable saddle, so what works there also works for general road riding.
I would suggest if you have a particular style of saddle that works for you in one configuration, you might want to consider a variation of that same style as a starting point for other applications.
-Kedosto