Hint: The answer won't be in a 3x3 table because it's not that cut and dry :)
The more words in an external link the less targeted that link is for for each word individually. So having a link that just says "widget" will help you rank better "widget" then an external link that contains the phrase "best blue widget". But both will help you as they both contain the keyword "widget".
You also have to remember that the keywords in the link are just part if that link's value. A link from a widget manufacturing website with the anchor text of "best blue widget" will do more to help you rank well for "widget" then a link from a Britney Spears website that links to you with only the word "widget" in it. This is because links from related sites are much more valuable then links from unrelated sites. Additionally, links from higher ranked pages for "widgets" will carry more weight then links from poorly ranked sites for the same term. So two links with the same anchor text can carry dramatically different weight.
If your goal is to ultimately rank well for "widget" I would start by targeting longer tail keywords like "best blue widget" first. Since it's easier to rank well for those terms you can achieve a level of success sooner. This will raise your visibility to other widget related websites from which you can attempt to get more generic links from that contains words like "blue widget" and just "widget". If you aim for "widget" right from the get go it could be a long term before you see the fruits of efforts.