(This is not covered in the plans.)
I added retainers to the forward and aft openings for the baggage areas. Without them, most things stored in the strakes simply slide out and fall into your lap or the laps of your passengers. The retainers are nothing more than strips of foam about a half inch high and a half inch high. I glued them in place, then covered them with 1-BID. If you want to do these, they must be installed as an add-on after the strakes are completed. The fuselage cut-outs must be trimmed even with the inside to the baggage areas so as to keep the BID tapes wrapped at 90 degrees in shear.