It might be easier to use the FEL without the toothbar for snow removal or use the heel of the bucket for dragging backwards (smooths out the ground). Also, extend the toplink of the 3ph for dragging the boxblade around, you only want to use the rear blade of the boxblade (unless you need to cut into the gravel). If you use the boxblade to push the snow, be careful, a longer toplink will make the boxblade want to dig into the ground and you might bend the 3 point lower arms.