For operations who employ class seven and eight size class combines, grain tank capacity and unload rates are virtually irrelevant. What does make a difference is the quality of the auger cart, quantity of trucks and capacity of on-farm or elevator carrying capacity. It makes no difference to me if I unload mid-round or after a round (I have a large enough aurger cart and plent of trucks that support class seven plus machines). Too many farmers want their grain tanks to be as larger or nearly as large as their auger carts. A combine's grain tank for most modern_progressive operations is nothing more than a surge tank for their large, high-performance, 1100+ bu. auger cart(s)- Balzer, Kinze, Avalanch, etc. You do realize that a 450 bu. grain tank voids all combine warranty and that no slef-respecting JD rep will take recourse upon his_herself to compensate you for hyper-extending your combine's grain tank capacity.