Trouble with GPO

Hello Fellow Sysadmins

I'm having a little trouble figuring out why a group policy is not applying to a security group i set up.

A little background: I have a WSUS server I'm trying to get deployed but wish to do a soft deployment with non critical servers first. I have tested with a few test servers I created on VMware. These test servers were added to a OU created for the test where the group policies currently resides. I created multiple group policies that cover each day of the week for install plus one "master" group policy that has all the information on contacting the WSUS server and any other policy required for it.

Now for these other servers that I wish to do a soft deployment for, they all resides in different OU, some under computer, one is a DC, and a few are in other OU's. I created a Security Group called WSUS and added the 4 servers to it. this Security Group resides in the WSUS OU. I then added the Security Group to the policy for WSUS and made sure that it had read and could apply the policy.

Last week for testing I did the same as above but instead was adding the servers individually to the group policy. Which was unsuccessful.

After a night of waiting (got tired left and checking back on it now) and doing a gpupdate /force, and checking gpresult I'm still not seeing that 1 they are part of the security group, and 2 that they have the group policy applied.

So my question is what am I doing wrong? Do I have to link the policy to each OU? Wouldn't the purpose of having a group in the WSUS container solve the need to link it to each OU?

forgive me if I'm mixing up OU with container.. Windows AD and GPO is not my strongest suite.