Excluding least used tags in WP_tag_cloud

Hi there,

For my website i’m using the plugin ‘Rounded tag cloud’. Customized it myself already a bit. But I have more tags than I want to show in the tag cloud, and want to exclude the tags that I used the least (say: tags for <2 posts). I have searched online and in the forums but haven’t found anything yet.

This is my code:
echo '<div class="rtc-div"> wp_tag_cloud('smallest=8&largest=18&orderby=count&order=RAND&number='. $options['number']);

Probably I’ve to use the exclude parameter. But how to use it properly?

It’s now displaying stupid tags that only have 1 post, and other (important) ones doesnt make it to the cloud, as they are staring with the letter Y or Z (Youtube/Zamzar)

You can watch it in detail at my site. Here is a link to my site.