Thanks so much, Eric. Any other creative solutions are very welcome.
This last post is what I've landed on as the best probable solution, I guess, too. You are right.
So basically, I would have students turn in their actual papers/projects in the advanced assignment with a "no grade" attached to it, but still be able to put their feedback there. And then I would enter a column in the gradebook for the desired point value so that grade calculations remain consistent with my desired point system. But this means the grade and the feedback are now disconnected when the student views them in the assignment feedback area.
Another workaround I've tried is just simply breaking projects up into units that are smaller than 100 points, but this then makes for a super huge activity list in the gradebook.
I think someone already covered the problem with setting up separate custom scales to get to your desired point value. This was probably the least successful workaround I tried.
I really appreciate all you do. And nothing else compares to what you can do in other instructional areas, so the workarounds continue to be worthwhile, certainly.