Not sure if I mentioned it previously, but the forward (downward hanging) edges of the forward seat floor panels were rubbing on the landing gear weldments.

I filed some clearance.

Used feeler gauges to ensure the clearance was uniform...

...at both ends (and all along) the weldment.

In order to ensure the clearance matched the angle of the weldment, I used a piece of blue tape to act as a guide when filing the panel on the workbench.

I originally started filing the clearance holding the file perpendicular to the edge of the panel. However, I realized what I really needed to do was hold the file parallel to the portion of the panel which lays atop the carry-thru spar. You see, the landing gear weldment is parallel to the top of the carry-through spar, so in order to have even clearance, the edge needed to also be filed parallel to the landing gear weldment.

Here's how it came out on the right side seat panel.

...and the left.

I also noticed the edge of the seat floor panel was rubbing on the side skin.

...so I filed a bit of clearance here as well.