Whats the most important segment of a barge (vessel) commissioning event?

ensure that the base blocks are evenly distributed.

There should not be any sagging and hogging while launching/commissioning.

the launching dock should be almost in level with highest tide.

This will enable the barge to glide/slip down with the tide without any damage to her hull.

If you intend to have a celebration,u can have it as you could have seen big ships being launched rite. i.e tie ribbons/balloons and open champagne

Do it near the barge ashore and not on the barge.Some owners are superstitious,so ask them for the dates and times.

Hope i was of some help.

Wishing maiden voyage.

Make sure the champagne bottle breaks on the hull. If it just bounces off that's a bad omen.