Carrying on with the post mortum. I looked at the core of the limb that I got stripped so it's just the wood. It's only 1/8" thick and then the grooves were cut in. That's from 7" out to about 13" from the centre. The horn is about 5/32" or there abouts. It's torn up so bad it's hard to get a good measure. The the sinew was about as thick as the horn and wood together but it varied more in thickness from the grip to the eye. It's hard to imagine that the wood added and structure to the bow. It's so flimsy. Do these numbers sound like they are in the ballpark? These are kind of averages so you can't get too much from them. It varies widely from the 1/3,1/3,1/3 but it was suggested that more sinew may be better for a beginner.
Yes, excess sinew will keep the bow from breaking. But if you have experience in sinew backing wood, i don't see a reason to overdo it. A 2-3mmmm thickness is enough. Originally those 42" short turkish bows had even only 50-60 grams of sinew (2mm layer).
I agree about the thinness of wood and horn, this is the problem with light bows. What can be done is made the bow really short and/or narrow. If one doesn't add as much reflex/strong kasan eye bend, he can put on more limb thickness and also keep the width less (and raise more thickness because of cutting width). This way the bow would still be 40-50 pound bow, but the limb would be more in proportion.
I have this kind of bows coming and i think its a clever way to have less gray hairs....
I don't believe in compression fractures. Horn needs to bend a ton more. It could have been a fracture somewhere that went down so fast, that there was no way to see what really happened. It happens. Thin, reflexed limbs are wobbly and delicate! Thicker, less reflexed limbs are not... While still being efficient.