This[1] is exactly what I'm worried about with a miswak. No way you're hitting all of your tooth surfaces.

[1] "Its bristles lie in the long axis of the stick, whereas those of a toothbrush are placed perpendicular to the handle. Thus, it is difficult to reach the lingual surfaces of the dentition with a miswak. Another disadvantage is related to the habitual use of miswak for a prolonged period... reported that chewing-stick users may excessively scrub the anterior teeth, which are located in the area of primary concern, while ignoring the posterior teeth. " https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3723367/#:~:tex....