Okay so...

What you have is the default maya setting that nobody really takes much notice of in its appearance. Ive caught even texture artists out with this one!!

Its just setting it to 1024 across the board.

I personally set mine to a grid of 10 x 10, so each tile reads as 0:1, 1:2 and so on. This is set up for use with mari essentially as Mari operates, 10 tiles across the uv space, it can go up as much as you like. This can still be used for photoshop if thats your prefered way

As you can see in my attached image, length and width are set to 10, so thats 10 across and 10 up. The grid lines are set to every one, so you will get one full tile instead of one subdivided into .1, .2 and so on, as in the default maya setting.

if you want to set each tile so you can see you are working 4k or 4096, just chnge the Subdivisions setting. You can see mine is 2....

If you want to set the tile to accomodate this simply turn this number up to 4094. Yes, this is two pixels less but it is allowing for the two pixels taken up by the thickest grid line. If you were to work at 1024 you would type 1022

Then hit the check box Subdivison lines. By zooming in you can see lines have divided up the grid 4094 times. This is an ideal way to work when laying out uvs for specific texture sizes and will allow you to scale uvs as need and judge how much bleed for texture creation between each uv shell.

A word of warning the subdivision lines can slow things down but once you have your uvs laid out you can turn the subdivs off.

hope this helps

Jay