The foot-box complicates the interaction of the angle of the suspension, the tightness of the ridge line, the length of the ridge-line, and sag. Specifically, I found that the calf ridge appears when the foot end of the fabric is loaded too much. Basically, the foot-box creates a hammock within a hammock. In a traditional gathered end hammock, both edges of the hammock will tighten as the hammock gets loaded. In the BB, the grosgrain line under the shelf tightens and acts as a traditional hammock side, but the load on the opposite edge of the hammock acts differently because of the foot-box. The centerline of the hammock starts to take the load and the calf ridge appears because it is one edge of the hammock within the hammock. For me, the trick was to distribute the load more evenly across the fabric. Here is how I did it, your experience may be different:
1. Understand the Asymmetric Lay. I found that a greater angle spreads the weight across the fabric better. More importantly, I paid attention to where my hips were in the hammock in relation to the ridge-line. Is my butt to the left, to the right, or in the middle? Lying on my back and then on my side also shifted the distribution of the load. I paid particular attention how these shifts in weight changed the tension at the centerline of the hammock at the foot-end, aka, the calf ridge.
2. Shift entire body toward the head end. This brings the weight away from the foot-box and spreads the weight away from the hammock within the hammock. Once I found the position that I liked, raising my foot-end or dropping the head-end kept me in that position. But, importantly, it wasn't just about cranking down on the foot-end. It is about hanging the straps at different heights or the ends at different distances from the tree.
3. The ridge-line should be taught, but not tight, when in the hammock. It may seem loose before I sit in in, but it will tighten as weight is put on the hammock. There is a video of Brandon showing that he can twist the ridge-line about 45 degrees when in the hammock. I found this to be a good test.
4. Adjust the ridge-line length to reduce shoulder squeeze. Sag is important in distributing the load across the the fabric and can be fixed by the length of the ridge-line. I spent too much time trying to adjust to get rid of the calf ridge, but had quick success when I focused on shoulder squeeze. Why? Too much shoulder squeeze means the load isn't being distributed across the fabric, and this will, in turn, impact the calf ridge. My aha moment was when I felt the line of grosgrain that is under the shelf. It was way too tight, and in my other hammocks that would have meant a lot of shoulder squeeze. In the BB, the pressure that is normally on the sides of the hammock is partially shifted to the middle of the hammock near the foot-box. I used an adjustable ridge-line to get the sag correct by focusing on the shoulder squeeze.
It is hopefully common knowledge on HF that the angle of the suspension will make a difference on how the load is distributed in the hammock. 30 degrees is a starting point, but between 26 and 38 degrees is the range for me. The typical mantra is to walk to a tree reach high, and hang straps. Great advice. But I found it is more complicated in a BB because of the hammock within a hammock. Which brings my next suggestion:
5. Have different angles for the foot-end and the head end by placing the the straps at different heights on the two trees. For me, I have found that my foot-end needs more of an angle than my head-end. Not just height, but angle. When hanging the hammock, I place the straps higher on the tree on the foot-end side. Shortening the length of the distance between the foot end and the tree can increase the angle. So if one doesn't have a lot of room, hang the foot-end closer to its tree than the head-end is to its tree.
Lastly, I have tried sleeping with my head in the foot-box, as Shug demonstrated on one of his videos. While lacking a certain hammock Feng Shui, it is surprisingly comfortable and works well for a strained neck muscles.
Hope this helps.