It to late now, but for the amount of mixing you have done over the last year, did you think on getting a mixer? I bought a secondhand one when laying 60m2 of slate patio and then sold it in after for pretty much the same price. It seems to be fairly common for people to do this.
Mind you, with all that mixing by hand you are getting a free workout.
Mind you, with all that mixing by hand you are getting a free workout.