Many unknown variables - how big are the trees you are going to pull (have you been given one of those forgotten gullies of jumbo trees), what is the size of the landing, can you get a mobile tailhold down the bottom etc ? Are there tracked bases to clear, process, sort and load the trucks ? A look through a few videos gives you a bit of an idea of shotgunning with a carriage on a swing yarder. (acme on TBird swing)
Discuss this in the forum topic shotgunning with the 124.