start with a nail punch. the coned shape of a nail punch will make it more resilient to bending v. a 1/16 punch. Order a Starett 1/16 punch from Brownells, they hold up pretty well.
Also, with a pin that is a PITA to get out will also be a PITA to get back in. Keep the pins in the freezer while working on the ports/block. Freezing the pins will dimensionally make them smaller and easier to get back in.
I just did 3 gas jobs last week and learned lessons the hard way.