For those who do, how do you gap spark plugs?

[dmjlambert]

So back in the day I used the slotted bender built into the gap gauge to bend the electrode. But I have found on modern spark plugs the electrode is very hard and the slotted bender bends before the electrode and there is often not enough room to fit the slot of the bender in there to do the bend. On the last batch I clamped the electrode with vise grips and bent it, but it didn't feel very scientific to be doing that. What is the correct way? I know a lot of people just leave them gapped at whatever gap they are at when purchased, but sometimes I want do dial in my own preferred value. Considering how seldom I do this I'm not sure I would get some $100 tool for it, but perhaps I could.