I have a small dust pan, a small shop vac with a long extension and well, my dog Troy. Gubb and Atts have been neutered for a while and still sprinkle a bit here and there. Their urine makes the box though which is nice as far as clean up.
My first rabbit Bailey was 100% with his box and only left poops around rarely, and then only 3 or 4.
I think adding multiple boxes and putting hay and food in such a way that they have to be in a box to eat helps the process. Buns naturally eliminate when they eat, so showing them to eliminate in a box seems to help.