Yes,patch engages rifling. thickness of patch will determine how tight. Sharp lands can cut a real tight patch.
Don,t sweat needing more than iron sights when live game the target. we owe it to them to be humane. On the range do what you need to for accuracy.
I,m about ready for a ghost ring site.
You only need to please yourself with it,unless in a ruled event requiring open iron sites.
Enjoy.