Piwik and TimeZones

So, I am trying to use Piwik on a SaaS application to power the analytics data for my users.
Is there a feature to use timezones when using the API to call the data? From what I understand, it’s not possible. However, I can specify a different timezone for every site. I will have to create a separate site ID for each visitor. Are there any problems I can run into? Scaling, for example?

Awesome app, by the way!

Timezones are per-website indeed!

Okay, nice. Is there a limit to the max number of websites I should create? It shouldn’t have problems with 10k+sites, right?