Remove peel ply from center seatbelt mount reinforcement. Some airbubbles in the front, but way less than 10%.
Opened up rear bolt carry through, and reamed front and rear out to 1/4".
That is is for Chapter 08 for the moment. The plans have you make the headrests, shoulder support and upper front seatbelt mounts, but I am planning a steel roll protection similar to Wayne's lovely WEZ, & don't intend to do that until the turtleback in on in a year or two. Not convinced about the headrest and shoulder support either. Doesn't have to happen now. Expect the seatbelts to be attached to tabs on the crossbars too. If this turns out to not be practical on the wider aircraft, can try a more hybrid approach like Chris's equally lovely BRN, or maybe somebody will come up with an even better idea I can steal.
Time lapse video of Chapter 08, and as much of CH09 as I got done before running out of materials here: