I don't have any of the larger CM albums, but I know the smaller ones I use are not true to size - and the CTMH paper 12x12 is actually 12x12. I think you would have to trim off a little of each side of the CTMH paper, and then it should be fine in your CM album. Side load or top load doesn't matter, because you would either create your page directly on the CM white/black pages or create your page and then put it on the CM white/black pages, because of the staple thingys that allow you to put them in the CM albums.
As far as stamping - really, anything goes! It depends on what kind of "look" you are going for, and what type of stamp you are using. I think you said you were looking at products online? If you pull up the online catalog, this is what I'm talking about:
Look for the stamp set called "Fair Blossoms". There are "solid" stamps, which appear all black, and there are "outline" stamps, which are outlines of the images. In the "Fair Blossoms" set, there are solid stamps of a large flower, three smaller flowers, a large leaf, two smaller leaves, and a flower vine. The outline stamps are of a large flower, a smaller flower, a leaf, and two leaves together. You could use the stamps in several ways.
1. Ink the solid stamp in the same color as your paper, stamp, this would give you a watermark or a tone on tone image.
2. Ink the outline stamp in the same color as your paper, stamp, and you'll have an outline of the stamp in a watermark or a tone on tone image.
3. Ink the outline stamp in black, then color in using markers, colored pencils, chalks, etc.
4. Ink the solid stamp in a color, stamp the image on a scrap piece of paper, then stamp the image again on your layout, without reinking the stamp. I've heard this called second generation stamping, and it gives you a lighter color. Then, ink the outline stamp in the same color, line up the outline image with the second generation image you've already stamped, and you will have an outline around the solid stamp.
If you want to see pics, let me know. If you're new to stamping, this might be clear as mud!