Xclock DISPLAY error while launching ./runInstaller after sudo oracle user

Question

I noticed ab old thread from 2009
xclock DISPLAY and sudo
and tried to hijack it away for my own question.
A kind forum moderator split my post out to let it stand on its own and have people (hopefully) pay attention to me instead of that original poster.
For me the file is .Xauthority and as my own user account I copied the file to /tmp. (the file is owned by <myaccount>:<myaccount>)
Then set XAUTHORIZATION=/tmp/<filename>
Then I sudo su - oracle, cd to oracle software: ./runInstaller
And I get the same error as the OP.
I changed permissions on the /tmp/<filename> and set the group of the file to be 'oinstall'.
Then I sudo su - oracle, cd to oracle software: ./runInstller
And I get the same error as the OP.
When I login to the server via vncviewer as my own account, 'xclock' works fine. It's when I sudo to 'oracle' and try to run ./runInstaller that I get the error.

Answer 1

XAUTHORIZATION should be XAUTHENTICATION in my previous post. I even changed ownership of the /tmp/<filename> to oracle:oinstall and it still doesn't work.
I've read a couple threads on the web that a certain set of rpms need to be installed but I didn't have any issues via ./runcluvfy.sh stage -pre crsinst ............. with packages.