I am evaluating SEP12.1  and looking for the following two options.

a) Under Policies-> LiveUpdate -> LiveUpdate Content,  Select a revision is grayed out. I would like to manually specify the revision number after the thorough test. How can I enable this feature?

b) If I have multiple client groups how can I control the "client updates" at the group level? I am not referring to virus & spyware definitions. Client updates are the updates to the client software and I would like to perform this in a phased manner.

Also normally what will be the file size for virus&spyware definitions?

Under Policies-> LiveUpdate -> LiveUpdate Content, Select a revision is grayed out. I would like to manually specify the revision number after the thorough test. How can I enable this feature ?

Can you post error screen shot ?

If I have multiple client groups how can I control the "client updates" at the group level? I am not referring to virus & spyware definitions. Client updates are the updates to the client software and I would like to perform this in a phased manner

It's not possible

http://www.symantec.com/business/support/index?page=content&id=TECH104435

Also normally what will be the file size for virus&spyware definitions?

See mithun comments

https://www-secure.symantec.com/connect/forums/normal-size-sep-virus-definition#comment-9143891

There is no error, it's just grayed out.

have you login Limited administrator user ?

Please post screen shot ?

My 2 pence worth 

Regarding the LiveUpdate Content Policy, I've not seen this issue before can you post a screenie please?  Typically, the "Edit..." button is greyed out until you select the "Select a revision" radio button for any given ef type.

Can you create a new LiveUpdate Content policy?  And check if SEPM itself isn't retaining enough defs?

High level content management info:
http://www.symantec.com/docs/HOWTO80884

Regarding the upgrade of management clients on a per group basis, this is perfectly possible.  All you do is select a group via the CLIENTS section of the console, and assign an upgrade package via the "Install Packages" tab.  More info below:

Auto Upgrade for Individual Groups

How to upgrade Symantec Endpoint Protection clients using the Auto-Upgrade feature

Finally, the defs size can actually vary wildly depending on the def type and method of delivery.  The full AV defs at the moment can be about 300MB (see below), but the SEPM is able to distribute defs as delta files, containing only the changes.  These delta files are significantly smaller

http://www.symantec.com/security_response/definitions/download/detail.jsp?gid=savce

You may only be setup as a limited admin, can you confirm?

I have logged in as admin and attached is the screen shot. I can not select the other radio button.

That's the only time I ever saw it greyed out.

Just a quick question, which follows on from my earlier post...

Can you check the below directory on your SEPM and tell me how many numbered folders you see in here?

<Program Files>\Symantec\Symantec Endpoint Protection Manager\Inetpub\content\{535CB6A4-441F-4e8a-A897-804CD859100E}

Along with what you have configured in Local Site Properties -> LiveUpdate tab.  I'm wondering what revisions (if any) the SEPM has stored.

Very odd. Confirm how many revisions you're keeping

How many definition revisions are you saving on the manager? Admin > Servers > Local Site edit properties > Liveupdate > Number of content revisions to keep

If this is set to 1 then there are no other specific revisions you can set the Liveupdate Content to so it will be greyed out. Set Content revisions higher and as the SEPM stores defs it should then enable you to select it. 

I will verify, by the way I have never updated the file as I do not have the Internet. May be that is the root cause.

Yea, if you can't get updates than it has no revisions so that would explain it

The "Select a revision" option only ever gives you a list of the revisions stored on the SEPM, not a list of all the revisions Symantec have released.

Therefore, to be able to select anything other than "Latest" from a LiveUpdate Content policy, the SEPM must be downloading updates and storing a backlog of them.