I don't recommend bending, as you're likely to overdo it.
The best recommendation is to roll the slotted tabs along a hard table edge (e.g. granite kitchen counter), it order to gradually and evenly push them inwards. If you just bend one tab, you'll likely overdo it. Then, if you work it outwards, you'll overdo it in the other direction. Constant working of the metal back and forth will produce metal fatigue and the tab will just break off eventually.