After having traced the instrument's contour on a plywood board, I studied its subdivision which I based on the converging of the strips, but I want to point out that not all originals are built this way: in some of them, in fact, the strips’ sides are parallel.
On the right side here, you can find the initial measurements I employed for the strips.

It is wise to plane all surfaces accurately, to prevent easy invitations to possible cracks. The temperature of the side bender is critical, and it must be found through experience. Spruce bends easily when wet, but at this thickness it does not bend gradually, rather it gives abruptly, so be careful to graduate your strength.

Bending the first strip should not be a problem: follow the desired profile, keeping the maximum height about 4-5 mm more than planned, because later we will remove some wood. The only bends on the outer face are to be done close to the neck and heel block. The reason for these is to provide flat surfaces for gluing, but most of all a solid edge at the end of the carving.