Server 2008 GPO ADMX / ADM Question

We have a mixture of 2003 and 2008 servers. All DCs are 2003 and this is not planning to change anytime soon.
Up to date all GPO work was done via the GPMC on a DC or a XP workstation with the relevant tools installed.

We want to configure the firewall settings for all the Server 2008 servers via GPO.

Ive installed the GPMC feature on a utility std 2008 server as Im aware Ill need to do this as 2008 and Vista use ADMX files now.

This is where Ive got up to but need to ask some guidance on:

1. Do I have to convert all my existing ADM files to ADMX using the MS convertor? Since I only have 2003 DCs I think not but want to ask just in case.

2. Do I have to have a combination of ADM and ADMX files on my DCs, i.e. the ADMs to service the 2003 servers and the ADMX to service the 2008 servers? Can they live side by side? Id intend to use WMI filters to have the 2008 policies apply to 2008 servers.

3. Is it best to have the 2008 servers in a separate OU rather than share the OU with the 2003 servers?

4. Where do I find the 2008 GPO files I need to import to configure the new firewall settings in 2008 and how do I import them? Is it like with 2003 where you just copy them locally?

Sorry to ask such questions, hope someone can help,

Thanks,

Reckon I’ve posted this too early as now have answered all my own Qs but thanks if you read this late and had some input.