Which set up to rent?

I will be shooting my old high school's Homecoming event, and will be focusing on field sports; football and soccer. I don't have the budget right now to buy equipment, still saving for a 70-200.

I do however want to rent some nice toys to get comfortable with shooting sports. I have narrowed it down to two options. I have a 5D2 currently with a 24-105.

Option 1:

7D + 70-200 f2.8 II + 300 f4L IS

Here, I would have the 70-200 on my 5D2 and the 300 on the 7D.

Options 2:

7D + 300 f2.8L IS Mark I

Here, I would use my 5D2 with 24-105 and have the 300 on the 7D.

The games will be all during the day, early afternoon for all. So inconsistent lighting is not an issue. Both options cost the same with the second being just slightly more. So, which would you go for?

I just rented the 300 f/4 and it was amazing. I was pleasantly surprised at the image quality on my 7D. I'm planning on getting a 400 2.8 in the future but I'll be adding the 300 for the versitility. I also own a 70-200 2.8 and that's a great lens. So if it was me I'd go with the 300/4 and the 70-200/2.8 on the 7D

Still seems a very close one. Have 3 more weeks to decide what to do!

For field sports, a 300 2.8 or 400 2.8 every time.