Your aggressive blanking of the disk was unnecessary. A fresh install will reuse all Linux partition space and format all partitions created, unless you explicitly prevent it from doing so, and will optionally overwrite all
partitions. If you just want to start with an apparently clean disk then "dd if=/dev/zero of=/dev/sdX
in a b c d ...] will blank the partition table instantly.
(32-bit) architecture, usually just labeled i386 will have both i386 and i686 (occasionally i486 and i586) packages. The AMD64/x86_64/Intel64
(64-bit) architecture will have x86_64 packages, unless the install is multi-arch (mixed 32 and 64-bit) in which case it may have any or all of the above.
If you want control over the installation use the installation media and not the live media. With CentOS-6 LiveCD/DVD you just get exactly what is on the live media installed to disk. Earlier releases are not installable from the live media. I suspect the screensaver is also due to the use of live media. If help is needed on getting the installed system working, then please ask about that in a fresh topic.
As far as documentation, if the upstream docs
and the Wiki
are not sufficient, then anyone is invited to Contribute