You'll need 2 or 3 sets of all libraries on a system. One for x86_64, one for x32. And if you want to support traditional 32 bit application you'll need the i6

You'll need 2 or 3 sets of all libraries on a system. One for x86_64, one for x32. And if you want to support traditional 32 bit application you'll need the i686 variant as well. None of these variants are ABI compatible with eachother. If nothing else, that's a burden on logistics.