Applicability rule for Adobe Reader Upgrade

Hello

I am currently working on updating our machines with Adobe reader 11.0.02 using a Managed Delivery Policy. Some of our users don't use Adobe Reader and  I don't want to install Adobe Reader for them. I was thinking of using Applicability Rule to determine if any version of Adobe Reader is installed and if not, don't install version11.

How do I go about creating the applicability rule? I know I can create a filter of machines with any version and target them, but I am more interested in using the Applicability Rule route. Also, since we have 32bit and 64bit OSs, how do I create a Smart Rule that will work for both OSs.

Thanks,
Husein.