Its very hard to say whether or not you can learn FI by august, since I barely know anything about you, but if all you worry about is the 3 against 4, then no problem.
It feels a bit complicated in the beginning, but after a few days or weeks you will probably figure it out, and then it will feel extremely easy.
Practice like this:
Play 3 notes from any bar repeatedly with the left hand and listen.
Then play the corresponding 4 notes with the rh in the same tempo (use metronome if you want).
Then go back to LH, then RH, etc...
Then play LH and try to add RH, do it over and over again util you fall into hypnosis

And try to make it more and more even. Play both hands and listen to LH, then listen to RH , and so on... and later try to hear both if possible.
Its good if you emphasise the first note of every beat.
And most importantly practice SLOWLY, but not too slowly, and try to practice in different tempi, but first only slowly.
Rev. etude is probably more difficult if you want to play it fast, but it depends on how developed your left is.
I remember that I thought the left hand in FI was a bit annoying too.
Also make sure you get that light leggiero in the right hand in FI and that you dont play too romanticly.