This week, I came back to this game after a year and a half break. I want to have a go as a chanter, and the idea of a gunslinger seemed very interesting.
How would this build change if you considered that I'm going to play on normal and with a full party?
You wouldn't need that many changes, because if it can stand by itself, it can stand in a full party. The one thing I would say is that this build is designed to outlast fights, and use a combination of blind and dragons thrashed to wear down enemies. You might be able to remove some of the defensive feats if it became a back row character, and move to a buff / dragons thrashed combo. The author includes a guide to changes for a party build in the OP.