Today, I got to work a bit more with the shorts. As previously mentioned, I had to widen the shorts due to it being a bit too small. While the two halves did not want to properly connect to each other previously, they now fit quite perfectly now. I’ve come to realize that the thighs parts sit so tight on my upper leg that it is no way I can make them to overlap like the screen-version. But on the other hand, both TK-409/Disney C-3PO do not have this feature. The screen-accurate See-Threepio has shorts which is not separate, but a whole piece that you simply slide on. The fiberglass shorts is simply of such a strange shape that this has not been possible without heavy modifications.
Here’s a picture of the shorts temporarily taped together. I still have to fix the “registration keys” to properly connect the two halves together. Then the plan is to fasten everything together with removable screws.
The picture below shows an appearance with Anthony Daniels and the Disney Threepio (TK-409?) from Star Wars Weekends 2011. Notice the gap on the back of the shorts, and the height difference between AD and the actor inside Threepio; he seems to be the same as height as me(!).