Size and risk
The share count comes from the dollar risk and the distance from entry to stop. A short borrow fee is extra. Not advice.
The arithmetic
You choose an amount of the account you accept losing if the price goes from the entry to the stop. The share count is that amount divided by the distance between the two prices, rounded down.
The dollar risk is then that share count times that distance. It can sit a little under the amount you chose, because of the rounding. It is not a forecast of profit.
Stop, target, borrow
The stop is the price where the idea no longer holds. A stop order is not a guarantee of a fill at that price: the market can trade through it. A target, if you set one, compares the planned reward distance with the stop distance. That ratio does not mean the target will be reached.
On a short sale, borrowing the shares has a cost. It is counted separately. It does not change the share count given by the stop. The My space page does this arithmetic with the numbers you type. It does not pick the ticker.
This is not financial advice.
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