Can I use ipe for backing? proper backing wood thickness ?

[dolgima]

1. people usually use bamboo or hickory for bow backing.  I used other hard wood(maple,ash) that have straight grain and it was ok. but can I use ipe, purpleheart,ebony, massaranduba?  These are very dense tropical wood usually used for belly.  I've never seen using these wood for backing. why??
for example, ipe backed maple bow is not good?

2. using same wood for backing is ok?

3. why backing wood is thinner than belly?  I've never seen belly, back ratio 1:1 or thicker back.   why using thin backing strip?

4. what is overpower? back overpower the belly , belly overpower the back   
If one overpowered the other , what happen?


sorry for my bad English.

[aaron]

with ipe it's very difficult to see the grain- pieces I have worked are not sawn to follow grain. This is OK for a belly, but not a back. I wouldn't do it. Grain violations in the back lead to breaking.
Overpower happens when the back is made of a stronger wood than the belly, - when the bow bends, the back doesn't want to stretch, so the belly must do extra compression. This extra compression leads to set or sometimes breakage. Bamboo is very stretch resistant, so it's often paired with a dense belly like ipe.
And why is backing thinner than belly? I think it can help the back stretch a little more to avoid overpowering.