First Grow Attempt

Week 8 The 2 topped plants have developed what looks like 4 main stems, 2 from where they were topped and 2 from lower branches that have caught up to the same height. The FIMed plant hasn't developed any clear new main stems, although it's lower stems have thickened a bit, it still hasn't really bushed out like it's sisters. One of the topped plants top growth has started to get a little lankier, bigger spacing between nodes & less outward growth. All the plants seem to be under some stress, lower branches starting to yellow & some leaves falling, but the middle-upper growth is fine. Could be nitrogen depletion in the soil, or the gnats may be causing them issues with nutrient uptake. The fly/gnat population has gotten a little bit larger, with 10+ flies (didn't really count) moving around. I've been watering with neem oil more often (almost every water now) & giving minimum 1 day gaps between watering, once a 2 day gap to try and curb the population, although I know the neem's effects are delayed as it makes the children infertile. Going to add some yellow stickies tonight & maybe catch some daddy long legs to move into the tent. At this rate of growth, I think I should be ready to flower in about a week, but I'm a little hesitant to if the gnats are still around, since I don't want them to be under stress through flowering, and the water will dry out slower under a shorter light cycle. How large should the gnat population be for me to be really concerned? I've been adding a light amount of nutrients as well with each of my waterings, figure it may help if they're having issues getting nutrients from their attacked roots, or if the soil is depleted, so I thought it couldn't hurt either way. With the gaps between watering I have seen the leaves canoing/cupping more often which makes me feel like I should be watering every day, but I want to keep the fly population under control so I haven't been. Is my watering schedule I good idea or should I be going more regularly? Not sure if the gnats of dehydration would be a bigger worry for the plants (maybe it'd be alright if I'm using neem every 2nd water?). A comment mentioned what I suspect to be gnats may be springtails, how would one be able to tell the difference between them? Any advice would be much appreciated. Update: Pretty sure they're gnats now, but the yellow sticky has been quite effective, definitely a large drop in population from yesterday. As long as I keep the soil a little drier than I have been, and maybe occasionally using neem oil & prevent them from getting out of control again, I don't think they'll be much of a problem anymore. I also think some of the signs of stress I was seeing was because the light was probably a bit closer than it should have been, so I've raised it. I've also added a small mint plant that I'll keep in the shade near the fan, hopefully it can act as a little preventative for pests returning, and maybe attract some beneficial creatures. Worst case, have some more mint to use