The dimensions for the satellite will be constrained by ESPA ring attachment (4 point, ¼” attachments)
This mount is limited to 180 kg, 24 “ x 28 “ x 38 “. So, the satellite is an octagonal prism, 60 cm across, 90 cm in length. The solar panels stowed on the sides will be within the allowable envelope (72 cm) making them 60 cm x 90 cm panels.