I didn't see this thread until today (and didn't read all in detail so hopefully this isn't too far off topic).
I don't have any comment about the angle adjustment, but I've been very happy with the one I built (set at 90). I decided to go with the option of using the miter slots rather than the jig riding on the fence. I also put t-track in the sled so I could use some "guides." One is small and simple for larger items, just guides placement while I hold the item in place. Then I made a couple more stops that could help hold a frame (squeeze from both sides with the plywood stops and hold with my hand down from on top to ensure the project doesn't shift upward).
Put a thick block on the back to cover the blade as a safety reminder to stay clear!
None of this is my invention, but rather a compilation of several ideas I found on YouTube when I was working on my wedding card project.
