Sure -
The way 2D Toolkit is designed is that you say what resolution you're gonna display the sprites at and what the ortho size is. The real resolution you display at doesn't matter, and it scales automatically to fill the viewport, maintaining aspect ratio (so if you expand resolution horizontally, you get bars rather than the image being stretched). This means that you can trivially 2x or 0.5x your screen, and everything just works.
The 1:1 button basically scales based on the sprite collection settings vs camera size, so if you 1:1 on a 960x640 vs 480x320, you should get the sprites being the same relative scale - again for the reason mentioned above.
For this approach to work with arbitrary resolutions, you can use the orthoSize method mentioned earlier, and that makes everything pixel perfect without touching or modifying each and every sprite. And with rich and potentially very complex sprites in 2D toolkit (sprites aren't limited to just rectangles), this can be a massive saving.
We also have the tk2dCamera class, which does things rather differently. Here, what you get is a self adjusting camera which will automatically adjust itself so sprites are ALWAYS pixel perfect. You also get the added bonus that 1 world unit = 1 pixel in whatever resolution you're using, and the coordinate system starts from the bottom left. the tk2dCamera also has support for anchors. Check out demo 11 - camera and alignment for more info. Seeing that your game is a puzzle game (and I'm guessing no scrolling), this might be a better solution for you.
There are 2 "bugs" with tk2dCamera currently. Firstly, the box drawn in the scene view representing the camera is incorrect (tk2dCamera uses a custom projection matrix, and the Unity scene view thing uses parameters rather than reverse projection). Secondly, the "Camera Preview" button doesn't display the correct data either - again for the same reason above. So if you intend on using the tk2dCamera, always look at the Game window.
Hope that helps.