Gorgeous crane! Beautifully done! But you have a major design flaw in your track layout. Tanks and offroad tracked vehicles have the track design rising from the ground at an angle front and possibly rear to facilitate climbing over impeding obstacles, tracked costruction equipment such as Bulldozers, Excavators and Cranes use a flat bottomed track design in order to increase stability. With your track design slopping upward the pivot point is now under the first small idler on the bottom, were it would be better directly under the axle of the big idler or drive, thereby increasing the footprint of the track and moving the pivot point much farther forward, allowing you increased stability and lifting ability at extended boom angles, thereby requiring less counterweight. Same at the rear as/if the Crane slews around.