How to change global affiliates commission?

Hi! How to change global affiliates commission? I found only that can change for every affiliate personally but can't find where is the global settings. On the main affiliates page anyway is 5%.

Version 1.5.3

in admin goto system->settings edit the store you are working on then goto the options tab it is about half way down that page.

Thank you! I thought I looked everywhere but miss that small point.

And one more question. Where can I remove payment options for affiliate? For example I want to disable "Check" payment option for affiliate.