I finished the top and bottom for my battery pack and I am quite happy how it came out.
When I had first tested my pack, I found the middle cells got a bit hot and the BMS got very hot, so I wanted to add some better cooling. I also wanted to add some convenience items like a capacity meter, voltmeter, and a charge port. Then while I was at it, I figured a fuse would be a smart idea too.
Although I have a number of fans laying around, I ordered a new one. I wanted to get one that had a high static air pressure value, vs high volume, so that it would suck the air through better. I smoke tested the air ventilation and was shocked how well it worked. It was drawn into the lower vents and blown right out the top.
Originally I was going to use threaded rods to hold it all together, but I did not have enough laying around. When I was test fitting, I found tie straps worked better than expected, so I just kept using them.
The pack came out great and works even better then I had calculated now that it stays cooler. I was about to mow my very tall grass in the backyard and it only took about 60% of the battery!