Trees, Shrubs and Conifers: Pruning Mariesii, 0 by Muddy1

Muddy1 wrote:
Some of you may have seen that I posted these photos on the plant i.d. forum. I didn't mean to do that, because I'm pretty sure this shrub is Viburnum plicatum var. tomentosum 'Mariesii'. I'm just trying to find out whether I should prune it and if so, how and when.
Plantfreak kindly provided some input, but I don't want to raise more specific pruning questions on the i.d. forum.

My only goal is to get a fuller shrub; I like its tall stature. If I were to cut it back, would it grow more horizontal branches and grow back vertically as well? I don't want to prune it only to end up with a shorter version of what I have now.