They are already a variable as the problem arose after installing knuckle studs.

Until you completely resolve the steering issue I would agree that the knuckles are still on the list of suspects, though I'd be surprised if they were the cause, but what you don't want to do is resolve the steering issue and not realize it because the upgrade created a similar symptom in a different component.  Nobody expects upgrades to not go well and the 25mm is a great upgrade, but if I were you I'd at least get the steering box isolated and see where you're at before tearing into the knuckles again.  The timing of things may make this the natural way of doing things anyways.