First they're cheap so don't reuse them, because you will never be able to grind the weld off in an arc around the tube. You also won't be able to grind exactally the same amount off of either. If you had a plasma cutter it might be possible, but you're opening yourself up to a lot of possible geometry problems. Cut em off, grind the welds down smooth and use NEW spring seats. Don't forget to reset the pinion angle to what you want before welding, also.
don