Yeah, I was building the fork mount myself yesterday morning. I basically made the same thing, two uprights with a long bolt traversing for the forks to sit on, and then a nut to tighten. While I was doing this though, I realized that it might be easier and better just to spend the dough on that Thule part. It somehow didin’t occur to me to build in an old hub! I bet that looks sweet. That’s an idea for next time.
Also, there was some debate about using the entire length of the wheel track between the two crossbars. Some racks seem to have it, some just have the little track in the back not connected. I ended up deciding that they don’t really matter that much and end up chopping them down.