I am glad you are going forward with this, and am looking forward to seeing the result. No doubt it will work, as it seems to have been done with good result.
My thinking is that in a direct comparison the muriatic will tend to bleach the wood and create a lighter result than the nitric. I say this due to the fact that muriatic is chlorine based. The saturation with iron being the main effect in the darkening of the wood.
I am also curious as to the comparison of the cellular structure of the wood after treatment by the two methods. I would think that there would be more cellular breakdown with the muriatic, resulting in a "softening" of the structure.
Please do post pictures and observations as things progress.