Potion Puzzle by Severus Snape: Solved!! ^^

"Danger lies before you, while safety lies behind,

Two of us will help you, whichever you would find,

One among us seven will let you move ahead,

Another will transport the drinker back instead,

Two among our number hold only nettle wine,

Three of us are killers, waiting hidden in line.

Choose, unless you wish to stay here for evermore,

To help you in your choice, we give you these clues four:

First, however slyly the poison tries to hide

You will always find some on nettle wine’s left side;

Second, different are those who stand at either end,

But if you would move onwards, neither is your friend;

Third, as you see clearly, all are different size,

Neither dwarf nor giant holds death in their insides;

Fourth, the second left and the second on the right

Are twins once you taste them, though different at first sight."

If you're a Harry Potter big fan (like me), you must know what i'm talking about here. It is the scene from Book 1 (Harry Potter and The Sorcerer's Stone), when Harry and Hermione tried to save the Sorcerer's Stone from being stolen by Snape (or at least that was what they think). Through a trapdoor guarded by Fluffy (nice name for a 3-headed giant dog), they encounter a room with these bottles on a table and a note, which happen to be a Potion Puzzle made by Severus Snape himself.

In the book, there's only the note (i mean the clues written above), no picture showing the bottles. So when i found this scene on Pottermore, i am so excited to solve the Potion Puzzle myself :D

Let me explain. There are seven vials on the table; 3 of them are deadly poisons, 2 are nettle wines, 1 is the potion to get you to the Stone ahead, and another one is a potion to trasnport you back.
And based on the clues above, this is the answer of what do these vials contain, from the left:
>>Poison, Nettle Wine, The one that'll bring you ahead, Poison, Another Poison, Nettle Wine, and the one that will get you back<<

in the book, Hermione stated that the smallest vial is the right potion to move ahead, and the rounded bottle in the right end of the row will transport you back. So, i'm right! ^^