Rob,
The boxwoods I have worked with are actually very easy to shape branches on but they do seem to take a bit longer than some of the other species to 'set' the branches...I have found some branches an inch or more thick may take a couple years or more to hold the position and bends you are trying to achieve...
In my experience I have found it best to plant the tree in a wood grow box and use guy wires on branches larger than pencil size...I have even used a 'turnbuckle' purchased at a hardware, in order to bend some really large branches...with this you can tighten it a bit more every couple weeks until you get the branch to the desired position, which, by the way I have found should be slightly past the position you wish to be the final placement...The boxwood always seems to relax back toward the original growth pattern somewhat...I also would suggest trying to anchor with guy wires in the opposite direction of the intended movement, to avoid strain on the root system of your tree...
I have never worked with the 'winter gem' variety...mostly with Korean, Japanese, and Kingsville, so possibly someone else can share their experience with this variety...
Regards
Behr
