if you don't have access to a local printer for ABS, you could try using craftcloud3d.com which bids out job on print farms all over the world.
(i'd used this service for printing parts out before i had my own printer)
i priced out black ABS (which oddly was less expensive than PLA) for the...
when i put mine together a couple of years ago, had the same problem. definitely an assembly issue of getting the bow attached to the right holes in the side pieces.
i see that some of the inputs require guessing about what's actually in your current tank.
from observations of my current vehicles, the fuel gauges are non-linear especially below the half mark (probably due to the odd tank geometries)
how does your app calculation deal with that issue?
i didn't realize that F-150's also used under seat vents just our Broncos until i found this while searching for bronco vent covers.
anyone have any experience whether this undersea system works well in the F-150's??