builder459
I believe you are going to need the HPH-24 or Regular Harvester - I would suggest the regular Harvester as it has the longer petals and will come off the 250 quicker and more smoothly. Then there really is a chance that you might need the HPH-12... It was built for the older Knights with the larger bores, what Knight called a .504 bore.
I have not tried them yet but I believe my Knight MK is going to end up using the thicker HPH-12.