Question about Tiled Background for building level

I have few questions for those who have experience building level using TiledBackground.

1. Is it ok to use only one huge TiledBackground object (Tile size is 32x32) to cover the whole layout,

or do i need to split it into smaller chunks ?

For example using only 1 TiledBackground object (tile size 32x32) to cover 2400 x 640 Layout,

instead of several small chunks, let say 10 TiledBackground object each with 480 x 320 in size.

I read somewhere (forgot where it is) that it's better to split bigger objects,

so I wonder if the rules still applied to TiledBackground.

2. Which method do you guys think is better practice to build level from Tiled Background,

something like this: (a simplified example, the real thing will be hundreds of tiles with different types)

<img src="http://i48.tinypic.com/2070r9g.png" border="0" />

METHOD 1

1. Less object, but some overlap happens:

<img src="http://i45.tinypic.com/169oy00.png" border="0" />

Only 3 objects (2 type of TiledBackground)

METHOD 2

2. More objects but no overlap happens:

<img src="http://i50.tinypic.com/21b2i6c.png" border="0" />

7 objects (2 type of TiledBackground)

METHOD 1 definitely is faster and easier to build

(however I wonder if those overlaps will cost a rendering time in the long run ?)

Thanks in advance

It's fine to use a layout-sized tiled background. Method 2 of designing your level will probably cause you to go mad, so I'd recommend method 1 simply because it's the only practical option. Performance should be approximately the same as method 2 anyway.