You're confused in GSF Position Sizer. We get it. You may be thinking that how can someone buy more shares than the amount we have, and position sizer is telling us wrong. The point you've to focus upon is say you have a capital of 10k and you put the risk at 2%. It means that, you are okay with loosing 200Rs if the trade goes wrong. Now what the position sizer does is it takes the loss over one share (SL% multiplied by Share Price) and divides the loss you can bear by it. So essentially you get the maximum number of shares you can trade with bearing the loss.
Coming to the point how you can buy more than the amount you have is due to the fact that when you do Intraday you are given margin/leverage (extra money by your broker- by default) so you can trade with the higher amount. You just have to close that trade/position on the same day. There are no extra charges. If you don't want to trade extra, simply trade with the amount you have i.e. divide your amount by your share price.
GSF Position Sizer concept is primarily for Intraday but for Positional Trading, the concept is slightly different, and as follows:
Say my capital is 1 Lakh, which I have reserved 50K for doing positional trades only.
Now my effective positional trade capital is 50K and I’m comfortable handling 3 positions at a time (You may take as many as you can handle on your own), which gives me 16.5K effective for each positional trade.
I stick with the rule of 5% risk (Loss I can bear on my own) over my capital in every “Positional trade” I undertake, so 5% of 16.5K is 825 INR.
Now my buy point was 4865.05 and SL is at 4479.60 which corresponds to 385.45Rs.
So, the quantity which I should buy becomes 825/385.45 which is approximately 2.
So I buy two shares of Bajaj Finance. I use this is RSI, MA80 and MACD.
The concept used for SL is the nearest support which was taught in the RSI trading strategy.