use a longer ball link in the a-arm. then lengthen the other 2 links going from the bellcranks to the swash. this will move the swash futher up on the main mast.
thats what i did when i set up your heli. I used a rocket city link and modified it to fit into the a-arm, if i remember right..
but be carefull... dont lengthen the 2 links from the bellcranks to the swash too far. the metal rods are not real long. the ball links will barely be screwed onto the rods. thats the issue i had when i built that heli. so i just went for +/- 12 degrees on the collective.
running 14 degrees is alot. the heli will bog real easy if you venture past 12 degrees. 14 degrees is used just for a quick pop of collective then your backing out of it again.