As long as they don't get too bulky, i go for fewer colas per plant. Reduces trimming time. Can easily snip them down to golf-ball sized nugs too. You can leave the lower level stuff too. Usually need to thin it out a bit, if you do. As far as maximizing a yield, that's the way to go. Trimming all that off doesn't equally increase mass up top, even if it does give it bump. Don't leave too much below and it won't impact it in any significant way.
it should all be an even canopy too... prune it up 3-5 days before 12-12, if necessary.
I like 9, or am trying 9 per plant in about 15"x15" space on the og cookies grow.. not in bloom yet. Approaching 2nd topping/pruning. 3x3 colas makes a square. shape of where it fits might impact # of colas. Stick to 1 every 4-6 inch x 4-6" and you'll do well. the ~4" would be better with fewer plants with more colas, i.e. smaller. ~9 is 1 per 5x5in space.
while i don't maximize yield, i should have excellent airflow. i've had mold issues before and take it a little more seriously now, lol. You can leave plenty behind underneath canopy and still have excellent airflow. Just thin it out a bit. spread out what you cut off so it's fairly even on each vertical shoot as best you can.
figure more colas = more work come trimming time, but probably a similar yield per sq ft. all other factors the same. fewer colas increases risk of mold and such. more plants means more work watering... but also diversifies risk a bit.