I don't think you can use the stock spindles with cando's control arms as the bottom ball joint is flipped and trying to taper the hole in the lower part of the spindle wouldn't work. I talked with Steve awhile back and he made sure I was using a drop spindle for those control arms.
3" will work fine, you will have to cut to lower down to 2" or so. You will also have to cut the lower control arm bracket that runs under the old mount so the new mount sits flat.