It would look like this -- http://www.wikitree.com/treewidget/Fougeron-2/300
Here's how to make this one yourself!
First, copy the code from one of the widgets on http://www.wikitree.com/treewidget/Fougeron-3/1000
Then look inside the code for a URL like http://www.wikitree.com/treewidget/Fougeron-3/2 or http://www.wikitree.com/treewidget/Fougeron-3/3. Replace it with http://www.wikitree.com/treewidget/Fougeron-3/200.
You might also want to adjust the height and width numbers in the iframe, depending on how it displays in your blog.