I have seen this set of pictures and looks interesting.
http://www.hornbow.com/cross.html
Before the beginning of V splice the core has the thinnest spot and in the kassan is slowing increasing his thickness (is basically not the limb but the siyah-kassan). This growth in thickness suggesting the limb become rigid to the kassan end - base of ears. This is common in all turkish/tatar bows. The amount of kassan flexibility from none in the otoman/tatar to more or less in the korean bow is not so big difference in my eyes. Of course, the ratio horn/wood/sinew could be very different between those bows and this also change the way how the limbs are working.
Regarding this issue, nobody said how did taper the core in the bows made here. In the korean bow both belly and core looks tapered, belly more than core. Tapering the belly is easy to made after the bow is sinewed, but the core must be tapered befoare, how do you know when ready?
Other question the sinew layer looks very thick, about a half of limb overall thickness, this makes the belly to work more than the backing, the belly being ?overpowered? by the thick backing. This can move the neutral line from center of the limb close to the belly (the exterior and hardest part of the bamboo) and compress the glue line. This makes me wonder if the grooving has the role to strengthen the bond only or also makes a smooth transition from horn compressing properties to wood when the limb bend. The grooved line is working not like horn ant not like wood, some between. Also this put the question if matched grooves really works better than non-matched?