If you have a CO2 pocket, you have more issues to worry about than how you will mount this monstrosity. Coupling warm kegs is a huge problem and it would not matter if you mounted it up side down!
If your system is set up correctly with consistent temperatures, you should not have any pockets. Hopefully you are using a gas blender and you keg pressures are in the mid 20's.
A problem you may encounter down the road is attempting to clean the manifold. Is there any feature which allows for dis-assembly and thus cleaning?
What is the function of the manifold? A couple of the
898B Beer "Y"s on top of a wall bracket would suffice.