i use a layer of the insulating styrofoam on the caul for bamboo.
lately, i wrap some sandpaper around a suitably sized mandrel, and sand a concave depression in the foam lengthwise- that cradles the bamboo nicely- masking tape the foam to the caul and do a dry run, and press, by hand, at the node points, to create a depression in the foam for the nodes- so that i dont have to do that when the glue is on, and inadvertently squeeze out the glue,
then glue up and band or clamp down- carefully re-aligning the nodes with the depressions,
i prefer bands- get a more even pressure- no high pressure spots- they are more work though!!!