On the "Raid de l'amitie" (Marocco) 2009 i used tubliss (DRZ400S), and in 2011 i used Michelin Mousses (WR250R). The tires were Pirelli MT21 Rallycross.
On the little bike, i think the mousse can last a very long time (3500 kms on the last raid, and the mousses are still there and in good shape).
The key, as said before, is the speed on tarmac: no more than 90/100 kmh, and they will last a very long time (i have friends using Michelin mousses for many years on enduro bikes).
On a personal note, i won't use the tubliss anymore: I had a flat during the raid 2009, and i had to change the tyre (a knob were ripped off completely, with a big hole in the tyre !)