Don't know if this is a new idea or not but......When reinstalling the pins, an easy-ish way to peen the drilled end without chasing the pin all over the garage is to place the tank so the drilled end is upward, place a small steel ball on the drilled end, then squeeze the head of the pin to the ball with a pair of channelocks.
If the ball won't stay put, stick it there with a touch of vaseline.