how many sites/servers can I run with my license?

am I allowed to run any wpmu plugins on a stand alone site? So far I have only used it on one multi-site that I'm still in the early stages of getting going...

But right now I have a big need.... I am migrating a site that has been running many posts a day for 6 years and has 6gigs of upload images (they didn't optimize at all and used horribly huge sized images because the client doesn't know what they are doing....

So I would like to try out wpSmushPro to 1) see how well it works, and 2) get this site optimized before I move it into my multisite network.

How can I do this?
Can I just install the plugin and do it or do I need the whole dashboard installed on that site?
Not sure what my license allows or if you can make an exception for me.

Thanks in advance for a speedy answer to this.