The exhaust port size is already too big as cast. Making them larger is certainly not an improvement.
You are correct that smoothing out the sharp edge on the short side radius is well worth it.
Again don't go too far - just get rid of the sharp edge - do not lay back the edge too far.

Some shops remove so much material from the short side radius and get into the valve seat - weakening the seat. There is no point going that far.

Cheers