Centrifugation (alone) is not the best way to make weapons-grade uranium. It wasn’t even feasible until the advent of modern day alloys which were both light enough and strong enough to withstand the forces involved in the process. Considering all of these things, it takes a lot of centrifuges and a lot of time to make enough substance (about a softball’s size), with enough purity (>90% 235-U), to be used as a weapon.

Iran has no problem diverting the resources to this end. If required, they can divert the entire GNP towards the process. Since it is no longer a secret, there is nothing slowing them down. As of now, they have 6000 IR-2, centrifuges running (so they say). There are many issues which can limit this process: The tremendous forces produced by spinning at this speed will limit the life-span of these devices. The vibrations, the stress to the bearings… everything is pushed to the limits of mechanical possibility. These challenges must each be dealt with. Depending on the number of pointers that Mr. Kahn sold them, depends on just how many hurdles they have left.

Even if they solve all of these problems… even if they devote the level of resources to these ends: the yield will be low. Maybe 1 weapon’s worth per year? In their hands, even 1 low yield weapon is enough.