Lift efoil board construction

I have a lift efoil. Now helping a buddy build his DIY efoil, he’ll do the electronics, I’ll make him a board … roughly thinking of cloning my lift3 4.9. Anyone know any specs on how lift has built and/or reinforced the battery box and mast area?

Doing some figuring today, and it seems the opening above the mast is only about 5mm thick, so my guess is the bottom of the battery box is solid carbon, versus having any foam under the box like I’ve seen in some builds on here.

My other guess is the mast bolts are just nut inserts in the carbon. I have seen other efoil builds where the builder inlaid strips of aluminum through the box area and extending beyond the box, both to strengthen the nut inserts and to add strength for mounting the box itself…that may be overbuilding but I tend to err on that side vs risk of not strong enough.

Any tips or suggestions greatly appreciated.