We will supply photo examples for consideration of course but we generally go for split flat sections of 1- 2 cm width. Generally we find it's much easier to buy the prefabricated strips from people using it to make the bamboo blinds commonplace across the whole of se Asia (though)
On site I note the presence of similar narrow timber strips, used for underside of soffit bed 3/4 - honestly, if it's easier to use this for ceiling in living I'm fine/happy but won't entertain any v.o - I'm offering this as a "make your life easy" option which mitigates the need for me to approve a sample etc. Ok?