It took a bit more effort than I envisioned to rework the belts.  One of the downsides to HTD belts is that they only come in specific lengths.  You can splice them, but the tensile strength is reduced by a minimum of 60%.  So when I adjusted the layout, the propeller hubs needed to be extended a slight bit to take up the extra length and I didn't leave any extra room on the ends, so I needed to cut new supports.  This wasn't too bad because I wanted to rework the propeller supports to flip the shaft mounts around and I did get to reuse half of the prop supports since some are different lengths.  I also left some extra on the ends in case it's needed later.  I think overall it'll help the design be more stable and allow for slightly larger propellers if they are needed.  The new belt layout is shown below.

The propeller supports have been flipped around and instead of a hole, there is now a slot to allow the entire propeller assembly to slide in and out easily.  This will make working with the vehicle much easier since the entire assembly had to be taken apart to take the propellers on or off.

The new tensioners are a big improvement, but took a lot of minor adjustments to really get the design perfected.  Previously the pulley was only supported on one side.  A longer bolt was swapped out and the pulley is now supported on both sides.  Two spring loaded arms are now used to provide tension to the belt.  Below is a video showing the tensioner for the single belt.  The double sided belt tensioner will now be built using this design.

I'm targeting to do another test during the first week of October.  I still have the belt guards to install, but the more difficult portions of the redesign are complete.   Design of the ducts and the rest of the hardware has started so things should hopefully go quickly once the test is complete.  I've also uploaded a new Semi-Finalist video in anticipation of Sunday's deadline.