You'd need to start by establishing what you actually want. Acrobat Reader is one product. Acrobat Standard is a different product. There is nothing called Acrobat Reader Standard, so it's not clear which you actually want.
Once you've decided, start here with the Enterprise Toolkit Acrobat-Reader Enterprise Toolkit Home . What you do will largely depend on your existing bulk deployment methods.
DO NOT buy retail product. This would be a nightmare to deploy.