is there any reason to worry about proper pitch?

Certainly. Under pitch the prop, and over rev your engine. Over pitch
the prop, and overload your engine.
Your engine should have a " recommended " rev limit. Pitch the prop to
get close to that figure, and your fine. I changed from a 16 pitch to
an 18 on my Chris, and get more top end, but now my trolling speed is
a little too high.