tax always comes down to 2 routes, 1 is Capital Gains or 2 Revenue Tax. If you are going to deduct losses and costs the profits will be taxed at company rates (28%), if you dont want to be taxed @ 28% - i.e. its CGT - then you have to hold on to the investments for 5 years and you cant deduct most of the costs.
If your thinking about trading through the company rather than your own name, the main difference is:
Private: Profits will be taxed @ 40% (depending on your tax bracket), Losses will be ringfenced if encumbered continuously.
Company: Profits taxed @ 28%, but you will pay DWT when trying to get that money out
Any scheme more complex rather ask a tax consultant.