White Balance Question

[Vihtic]

I'm using a Canon T3i and for a while I've just been using pieces of white filler paper for my white balance. However, I want to invest in an actual white balance card with a correct neutral color. I'm trying to decide between these two.

http://www.amazon.com/gp/product/B004G3NW5M/ref=ox_sc_act_title_3?ie=UTF8&psc=1&smid=A2LXBKOLL3J3K6

http://www.amazon.com/gp/product/B004G3M36Q/ref=ox_sc_act_title_2?ie=UTF8&psc=1&smid=A2LXBKOLL3J3K6

I'm leaning towards the second one because it's a bit bigger, but I'm worried about the crosshairs in the center. If I take a picture for my custom white balance on my camera, will the black lines affect it at all? Also, how much of the frame should I fill up with the white color?

Thanks

 

[CraigL]

In this case, I definitely find bigger is better, my grey card is A4 size. The black won't matter, it's looking for colour shifts, as long as it's a consistent black, it won't introduce any other colour, so it won't skew it.
With ML installed at least, when you click the Auto WB button, it shows a square that indicates what area it's sampling for the colour shifts.
I think that the stock ROM does the same thing, I don't remember.