Volkan,
For vertical you want a bigger prop with less pitch, think of it in terms of a heli blade. Something like a 12x6 or 13x5 which won't have the top end speed but will give you more thrust. I prefer to prop aerobatic planes for less speed and more vertical performance so I get consistant uplines and shorter take off runs. They also are less twichy at slower speeds and you can do more with them. It's like running in first or second gear instead of third or fourth. Experiment on what works best for you.