With a 29" inseam you could go to even shorter cranks of say 155mm or 150mm. They're not easy to find but they are out there. I built a custom bike around 140mm cranks and I've gone even shorter with the cranks since then. As well as making it easier to spin higher cadences, shorter cranks reduce leg movement which reduces the rubbing against the saddle. If a frame is designed properly for shorter cranks then the seat tube angle will end up being more relaxed than currently used for small frames, which will move the riders weight backwards over the rear wheel, which will take weight off the riders hands and shoulders.

Anthony