Big problem with the turret of the T-31: trying to correct all those bubbles, I've broken the turret a first time. Trying to make a reparation, the turret falled out of my hand and broke again. Definitively: two reparations, too many bubbles... Work would be too hard. So, T-31 project is definitively abandoned.
Never mind: I will build my Dragon Sherman from the box; it's a great kit in itself!