well, the answers often actually vary! maybe that is why they seem varied.
since it is your first try inside, go with 2. you will find it easier to tend. as they grow they will get big and 3 would be too many when they hit late veg.
i like 5 gallon pots, but that is just a personal preference. i find it easier to water and mess with the plants.
learning how to ask questions on google is the key! if you use google, add "thcfarmer" at the end and when you get conflicting info ask. it helps people helping you if your question is specific, for instance instead of "what do i do?" try "ive read about such-n-such and should i do this or that?
like right now i am concentrating on where and how to dry my plants, im getting near the end of my first grow. so i am reading all the threads here on it and making a list of what i need and need to ask. so instead of another how do i do it question, i will be able to ask a good question (and i have a few!).
i think your frustration is self inflicted. you started a grow and then started to figure out how and what. turn that around, figure out your plan, then start. your frustration levels will be much lower if you approach things ready to do them.
like with the light, that is pretty much math, if you have a light it shines at some angle and that is your coverage. you have a phone and can get an app to see the readings and know if it is what your plant needs. you didnt do the work, just asked how many. naturally you hope to just be handed the answer, but you know what? it frustrates the helpers to think you put nothing in and then want them to do your homework for you. it is very frustrating now, trying to help, to even get at what your issue is? what issue was so bad that it prompted such an insulting post?
so... is that it? how many under the light? we all suck because you cant get that answered? and it has what to do with ph?
see? now THIS is frustration! try and try and try and then get insulted and cried to for help and then again try and try and try just to get each response with a whiny "ya but no one loves me".
you start a thread and dont even have an issue? did you just wake up and say "i think i will insult the wonderful people at thcfarmers because i dont feel like googling"