Barrman: Upon reviewing your bikini top photos, I thought to suggest to you an idea I have used in the past for a CJ bikini top. In my CJ, I disliked the large amount of wind flap from the top, as it appeared to never be taut enough no matter how tight I pulled the strap (I too have resewn the straps many times).
A simple solution I used was to take a piece of scrap wood and bow it through the center. The wood was approximately 1" x 3/4" and an appropriate length that required flexing or bowing the wood upward in order to engage the ends into the inside lip of the windshield (specifically on top of the footman loop) and a point on the rear top support. The installation is done after the top is mounted. The wood ends provide only a physical attachment to front and rear, so the specific length requires a tight tolerance.
Although the bubble appearance from a front end view may not be aesthetically desirable, it cured the wind flap, as well as the requirement for yearly strap sewing maintenance. After a short period of time with the wood mounted, it will maintain the nature bow or upward curve, thus allowing for easier future engagement.
Lastly, due to the inexpensive nature of this wood part, it is easy to replace periodically when misplaced, damaged or used for other purposes, and it does not require mechanical anchors or a designated storage area. The part is simple, light and unobtrusive.