so i started printing this and then my print failed which was fortunate for me as I soon realised the holes were way too big for my carbon. I have the nevermore carbon pellets, but not every carbon pellet is full sized. They have the right diameter but some get broken in the packet over time. The result was that more than a few pellets fell through the grate when I tested it. If the rectangles were slightly more narrow then this could be averted. I ended up using the VEFACH modifier in super slicer to create a modification layer using hexagons which worked for my pellets without changing airflow much. They don't have the best instructions for this, but it is the same as adding a hexagon layer to Voron skirts.