I am making Hamelman's 3 stage 70% sourdough rye and am on the final sourdough stage now.  Pretty soon I am supposed to mix in a large portion of flour and water.

Hamelman calls for a spiral mixer, which I don't have -- not even a stand mixer.  He says to mix it on the lowest setting for 4 minutes and 1 1/2 minutes on the next speed up.

Can't I just use my hands to mix it in, and if so should I do it over a period of 5 minutes?  I guess I need to try to be really gentle with due to the sharp edges of the rye bran.

Any help would be greatly appreciated thanks.