Lara, I have been growing vertically for many years with great success. Here is some advice which you may find useful.
First off, I never use a "bare bulb." In any properly done vertical grow, there is always some kind of reflector involved; at least one flat reflector directly above the bulb, at a minimum. There is a ton of light that, if not contained and reflected back onto the plants, will escape from the top and bottom of the bulb.
Use a flat reflector with hole cut out for the bulb to hang through (you can build something cheaply), and one on bottom too if you don't want to put plants below the lights....which you can certainly do as well, with great success.
In my opinion, the only way to go is to rotate each plant one half turn each day. This will ensure the plant develops evenly, and yes, you will get large nugs on the entire plant, with very minimal larf...which also saving yourself a lot of pain and trouble of training, trimming, and all this other B.S. that people currently waste their time doing.
Think of each branch as its own individual plant. If it's shaded and kept from the light, it will wither away. If however each branch is able to get full light at least every other day (rotating half a turn a day), it will be quite happy with that arrangement and will develop fully.
Once the plant is well into flower, you can pretty much stop rotating by that point, as it won't get lopsided.
I'll be happy to post some pictures for you tomorrow....of wall to wall nugs, in a 9.5' x 9.5' Growlab tent with 2k HPS. That was a continuous system where I was always adding in plants to flower or harvesting them. At full capacity, that tent generated enough nugs over a couple month period that I was still rolling blunts a year later from grocery sacks of nugs found stashed in corners.
