I’ve been using a Matchfit Wasteboard on my AltMill 4x4 from the designs that came from the Onefinity forums but after using it for the past 8 months I found some changes that I thought would make it a little more usable.
Originally I had made it on 100mm centers, but the AltMill being 48"x48" (or there abouts) meant I ended up with an awkward transition on one end, so I decided to go back to 4"x4" centers. I made mine with dog holes that I can just shove cut bits of PVC Pipe in which allows me to not worry about hitting the dogs with a bit. Most of the dogholes go almost all of the way through 0.7" into a 0.75" MDF, but the ones which also have the mounting points in them go only 0.5" through to give more material for the screw to engage. I have matching threaded inserts in my baseboard to screw the board down to.
I also found that the entry points for the Matchfit all being on the ends was problematic as it makes clamping at the very edges impossible, so I re-did this with alternating entry points, some on the end and some inset so you can move the piece back out to the edge.
The final result looks like this:
