I agree. a 91fx should be fine.
Volkan, you may need a little more padding around the fuel tank if you want to avoid bubbles. Also, a note to all Leo builders, You will need to re-enforce the lite ply servo mounting tray as this will distort the moment the servo is under load. I glued and screwed 4mm ply underneith the existing servo tray. One other mod, if you wish to use the stock hardware (which is of good quality) you will need to strengthen the elevator pushrod connections. I zapped the pushrods into the dowl, heat shrinked it, zip tied it and added a layer of glass cloth around the connections. This ensures a slop free and very strong servo to control surface connection.