Sorry for the late reply sensei, i had some real problems that i needed to solve in real life so i couldn't log in for a long time, even if i could i wouldn't have enough time to reply to training threads.
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1)
How the technique is performed:
I begin by gathering a small amount of my chakra then i perform one quick hand seal, as i do i disturb the opponent's eyes chakra flow, then i use a smaller amount of chakra to travel around my body and copy it's shape, i start to concentrate my chakra and in my imagination i use the shape chakra to create an image of myself, just like a clone technique, so since i'm already disturbing the opponent's eyes chakra flow, and as i grab a kunai with a paper bomb attached to the end, i automatically disturb some of the enemy's brain cells, which makes him confuse the kunai and the paper bomb with an image of myself, but since i am using a small amount of chakra and attacking a small amount of brain cells i only sicced at making him confuse a single kunai with an image of myself, which is the kunai that i'm touching with my hands (That's why people with huge visual powers can never be effected with such technique).
So as i throw the kunai the enemy automatically confuse it with an image of myself, and logically the enemy shall think that i made a clone.
What senses the Genjutsu affects and how it affects them:
Vision.
How the genjutsu creates an opening for the attack:
I think the Genjutsu itself is an attack and countering it under the pressure of combat and the pressure of being in short range is enough to make them get hurt easily, but i would use another attack (fire or lightning attack) to put them under more pressure.
In what situations would use it, if you would use it at all (With reasoning):
Well since this jutsu is made for short range opponents i'd use it as soon as the enemy gets to short range.
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2)
How the technique is performed:
I start gathering some of my chakra then i make it split in two, the first part (just like in the first technique) copies the shape of my body and i use it to create an image of myself in my imagination, i the other chakra part to manipulate the enemies' sight again by disturbing his ayes chakra flow, then i add more chakra that i use to increase the amount of my illusionary clones, then i spread a very small and thin amount of my chakra all over the place and then i execute the jutsu by connecting the disturbing chakra with the shape chakra and the chakra on the battlefield, by doing so i make the enemy believe that thin battlefield chakra is a huge number of clones that emerge from everything (trees, earth, rocks..), the movements of the illusionary clones are quite slow, but every time they get hit the multiply, and it's quite hard for the enemy to figure out that the clones are an illusion because when they get attacked they act like ink clones.
What senses the Genjutsu affects and how it affects them:
Vision.
How the genjutsu creates an opening for the attack:
While putting the enemy under the pressure of fighting a huge number of enemies that act like freaking zombies, i can get behind them and launch a strong attack, because the illusion can be used as a method to block the enemy's field of vision.
In what situations would use it, if you would use it at all (With reasoning):
I'd use it when i feel like getting away from an enemy that is about to overpower my techniques so before they get the chance to do so i'd use the illusion to launch a fast attack or to get away.
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How the techniques relate to each other:
Well you described it all

Okay both techniques create illusion clones but the first one requires more concentration and makes the enemy co,fuse an object with a clones while the second creates many illusion clones, but both of them can be used in a beautiful battle situation:
*So in a battle while i'm mid range away from my foe, i cast the second Genjutsu and create many illusionary clones, then the enemy gets confused with the huge number so i jump in the middle of the clones and i throw the Kunai with the paper bomb and make the enemy think that one of the clones is running towards him at high speed while in reality he's getting attacked with kunai.*