multi questions api

(1)a category is a rule. if i have 10 categories or rules, can it be set to 1 hour and the software will fetch every hour? (2)can each category or rule have more sources? (3)how many feeds can be shown under each category ? (4)if the purchase key was used in the api key area, will it fetch from the old api? or not work? (5) will having it auto fetch every hour,will it slow down website? (6) will having more feeds shown under each category, slow the website down? (7) in my account it says i have 400 something daily calls, can users go over this if they fetch every hour, from 10 categories or rules?