I don't know about the 1172 x 864, it may well be possible on some systems, but is not available on mine in Windows ME. The aspect ratio is slightly different if you do some sums. 1.35 instead of 1.33
If you want more screen space but find the fonts too small to read in 1280 x 1024, change the font sizes from the appearance tab for all text items. You can also increase the width of the scrollbar, active title bar, active window border, etc.
If you take some trouble, you can get exactly what you want. Save your desktop scheme under a new name, and save your existing scheme before you start, so that you can easily revert, should you need to.