Hi Claire, welcome to WhitneyZone.
Unfortunately, the Inyo National Forest prohibits transferring permits. However, you could
join into somebody else's group if they had two others drop out. But then they would be responsible for you as part of their group.
On the other hand, you might just show up at the Visitor Center and try for a no-show permit. There are many groups who have reservations where some of the party drop out, and there some entire groups that don't show up. These permits are made available at 11 AM on the date of entry for the hike.
If you are there at 11 AM, and if there are more asking for permits than are available, they hold a drawing and process people in order drawn.
But look at the unused Whitney permits for 2009
. Of all the weekends you have given, the first one in mid-July looks best. It appears there is a lull in the permit demand after July 4 for a week or two.
And IF you could show up earlier in the week, you can practically be assured of getting a permit. Those numbers are the number of unused at the end of the day, not what was available at 11 AM. Most mid-week days always have unused permits available.