Brokerage is classed as a financial service and therefore only 75% of the GST can be claimed; but you get the GST input on both sales and purchases brokerage fees
Agreed just treating all shares as inventory is certainly the easiest and simplest way to go; but keeping each buy and sell in a spreadsheet gives you the option of which particular shares you want to sell and so maybe minimise tax if you have had success with other shares
I know what you mean about accounting fees, but as an accountant I don't have to worry
At the end of the day whether you claim GST or not does not make any difference to your overall profit or loss
