yeh most come in threes or twos its because certain chemicals change when they contact others in a mix after a while, they become salts(?) that the plant cant use so they cant ship as one or it would be ineffective.
also why you should mix micro into the water first, stir, grow, stir, bloom (or so i was told atleast)
i have fed every time prettymuch this grow with no real overfeeding signs. muddy on here says to feed lightly every time and let about 15% runoff from the pot so that gets rid of the built up salts. it seems to be true anyway im feeding over the shedules for photo plants recommended ml's cause they seemed hungry i just worked up slowly and watched out for signs of overfeeding. one of the plants got a bit screwed by it i think but the others are fine anyway. just got too green and got some mutant leaves but its a nice plant anyway and big enough still. that was due to my lazyness giving them all the same feed instead of tailoring each to what they needed.
others alternate water and feeds to stop buildup but its the same idea and constantly feeding carefully lets them have all they need when they need it.
i never flush its more for fixing problems with your soil, extreme ph or overnuting etc. at the end of the grow i just feed water no nutes. only doing it for around 4 days this time. but i tapered off on the feeds to low levels. most do that plain water for a week or more.
i chopped a plant last grow cause of a herm day after feeding strong flower nutes and it was fine no bad taste or anything. i think thats more from overnuting near the end.
keep up with your runoff ph and lockouts shouldnt happen without drastic overfeeding. just start low and gradual.
different strains have different maximums.
also yours are looking great, look back at the start of my journal theyre not far off that possibly even smaller.
this is day 24 for the smaller ones for comparison. i think you have one node more than me in those pics from the same age.
end size is down to how many problems you had early on, pot size, whats available to it (air, food and light) and luck in the genetics i think. just try to get close to perfect on every front!