Good. Those two widgets look like they're lining up the way they're supposed to.
Now, I think I have it. The pixel dimensions in Photoshop are still throwing me a bit... on screen it shows a 7-pixel gap between images, but the math of the widget sizes says 6-pixels. Hopefully, this is it:
1x2: 74x154
1x3: 74x234
1x4: 74x314
2x1: 154x74
3x1: 234x74
4x1: 314x74
4x4: 314x314
3x3: 234x234
2x2: 154x154
1x1: 74x74
NOTE: I revised these dimensions on 10/29/10. If these don't work perfectly, the heights may still be off (ie: 73, 153, 233, 313).
I based all of this on your last screenshot, which measured the 4x1 at 314x73 and the 2x1 at 154x73. I then took that into account with the 1x2 selected widget in the screenshot before that, which was at 76x154 (then I deducted 2-pixels per width and height to come up with the actual image size).
Let me know how this works.