its not that hard, iv had to put in longer screws because the mech is so old, but the newer mechs should be ok with winding them in all the way, u can us single speed spacers to put in to make the 3 gears you want central, and then use the tension of the gear cable to allow u to shift, along with the actual H L screws. It takes a little fiddling, but its nice once its done.

 im lookin at running 3 speed on a hope pro 2, how do you set it up so that you dont go up or down to many gears ? thanks