1) you could use additives such as riverstone or gravel to line the bottom, something to that effect even if you just use rocky dirt from the back yard. I use riverstone/brookstones myself. Helps prevent packing and poor drainage issues. I also like to top the stones with rootballs from field weeds cut low on the stems and pulled up. Takes up about 6 or so inches of the bottom and less bags/shoveling, the rest of the pot is useable soil.
2) Half your plant size is going to be that "sticky bud rush" it`s like a second geer for the plant at flowering, CDB plants pretty much grow the same slower rate from the no so good plant`s I`ve seen.
There are strain wizards here at RIU too.
3) Bugs, mildew/molds, more bugs, birds, wind, rain, more bugs, plant illnesses, sunlight direction, animals, tie downs, odors, and more bugs.
4) Rippers, cops, nosey people, questions, sales, quality control,...and people you shouldn`t have told.,
Your dream will be what you put into it. 4lbs per plant ??? ..... I`ve seen much more than that. I left behind more than that in junk bud.