1870s load analysis says that the further the bearing is extended out of the press fit in the head tube, the more the radial load on it will tend to tip the cup out of the head tube.
How big a problem is that likely to be considering you've got the stem and gubbins loading everything? Couldn't one counteract the problem by having a longer press-fit 34mm section?
1870s load analysis says that the further the bearing is extended out of the press fit in the head tube, the more the radial load on it will tend to tip the cup out of the head tube.