to put it as simply as possible: keep 8 in bloom and 4 in veg...each 1 in bloom a week apart..harvest one plant every week or so, skip harvesting a week or two here and there so your plants get 9 or 10 weeks...you will have to go from clone to keep up at this pace however so each time you cut one down you need to obtain a clone for the veg room, from your own plants or a friend/dispensary.
this is what I do except I have 4 patients, you just gotta keep each plant a good distance from the light as they are all different size cause they are at different stages, I use crates to adjust each individual plants height and keep my light high up on the ceiling. The canopy is never 100% even so its not the best but it works out good with our medical system..again not the most productive and no real comercial application with this method but it is perfect for a personal stash because you can have a lot of variety also and you harvest every week around your maximum limit of 2.5 ounces