IB,
I cannot tell you specifically for the 430 loader, but I assume it would be the same as with my 300cx. The boom blade for mine was about $1200.00 installed, meaning running the hydraulics and the extra lever needed for hydraulic angling, which I wanted. You can get manual angling, which is fine, the hydraulic is easier though. I believe a 72" blade is about the biggest I would get, though. Be careful not to confuse this with the 74 Blade, which is a frame mount, and not 74" either. They make an 84" boom blade which your 4310 would handle, but it is so wide, it is cumbersome. The 72" even when angled maximally, still will plow greater than the width of the tractor. I do not know much about the Curtis blade, but our local dealer says the lift system takes some fabricating to work. After seeing the JD blade, he said he liked it better. The moldboard is not quite as high though.
John M