Along with the Kadomatsu papercraft, I also downloaded the Reindeer and sleigh from the Yamaha site.
I started with the sleigh. It's 4 sheets, and again I used 0.18mm stock. The actual file is in PDF format, which can be imported into Gimp one page at a time. The design is a simple white on white, so in Gimp I painted the pieces brown and tan just to see what would happen. The first few parts assembled fine, but the undercarriage sled warped from the glue. Fortunately, it's not normally visible, and it did warn me about what would happen with the larger flat blocks on top, so I made sure to place a small book on top of each one as the glue dried. The only real problem I ran into was that the sled cowling was drawn about 0.5 cm too short in the original plans. In fact, the paper runs out right at the top edge of the hood, where the glue strip part should start. I covered this with a folded length of paper to act as a reinforcer and to make it look like the white trim was intentional. Overall project time was 4 hours.
I then tackled the left-side reindeer. This was the trickiest thing I've made from Yamaha so far. Again, there's not enough written instructions to know how to put everything together. Also, you have to pinch the paper along the center lines of the legs and antlers to give them more of a 3-D effect. This alone took forever. What gave me the most trouble though was in figuring out how to attach the rear legs. There really needs to be markings on the body itself to indicate the glue tab points. By the time I got to the forelegs, the glue had dried enough on the back that I couldn't pull the back legs off to reposition them. The result is that it looks like the thing is squatting. Total time, 2 hours.
When I got to the reindeer with the raised front leg, I knew more about what I was doing, and I rolled the paper of the body to make it wider and puffier. I wrapped the glue tabs from the legs so that they'd attach better, and I spent more time determining how the legs would stand before attaching them. Then I discovered that the antlers attach to the head, and the head to the neck, in a different way than what I used on the first reindeer. So now the head looks weird to me. At least the reindeer stands up better than the first one does. Total time, 2 hours.
The next flaw in the design is that the circular harness that the two reindeer fit inside for pulling the sleigh was drawn at least an inch too long. The resulting harness loop looks twice as big as in the assembly instructions picture. I had to cut both loops and resize them to fit the reindeer better. I get the feeling that the artist altered the artwork for the sleigh just before publishing it, and neglected to test build it to see if he'd screwed anything up. This is definitely a case where you need to check each subassembly several times before gluing anything. Because another thing you'll catch is that the back of the sleigh is too heavy for having only two supports at the front half. I'm using a pencil sharpener to prop up the back end and hide the sagging.
Still, the entire display looks fine from a distance, and it's serving its purpose as a big greeting card (rather than my going out and spending $15-$25 for something the same size from Hallmark).