My usual inking procedure goes like this:

I begin by outlining the panel borders with a fineliner and make sure to leave spaces for speech bubbles that go outside the panels open.
Then I ink the speech bubbles with a G-pen.
With the G-Pen I can vary the outlines of the bubbles in width to make them more lively and dynamic. But it‘s really just a matter of taste how you want your bubbles to look like. If for example you want a cleaner and cooler look for them, using a fineliner, rapidograph or Maru pen would be better.