For your homepage: Do you only add the keywords for the homepage OR do you add all keywords that will be used in all pages within your site in your keyword description??
I believe the phrase that Ken uses is "keyword focused content pages". Each page, including your home page should be focused on one keyword
. You will, however, find that it is almost impossible to build a page without mentioning a few of your other keyword on your list...
The page should be focused on one keyword even though you may mention others. Do not mention the other keywords often though as this may dilute the focus of your page.
The keyword for your home page should be one that reflects the theme of your site.
Should their always be different keywords in your tier 2 and 3 pages than what would be in the home page keywords???
Your tier 2 and tier 3 pages should usually focus on a different keyword even though there is nothing wrong with writing more than one page using the same keyword. The content should, however, be entirely different. Furthermore, Google will only list one page focused on a particular keyword.
I hope this helps.