You may need a re think into your light set up. I've got same set up as you but in a 60X60 tent and I'm being slated for having far too much light in it. Could you use a 6k on one of your spare heat sinks and a far red cob on the other spare sink and only run 3 of them at a time depending on whether your in grow or bloom stage. I'm thinking of something like that for myself.