The second option for slightly heavier fabrics is a lightweight waistband with a simple placket opening.
Placket closures work much better for larger sizes, a side opening can gape when there are ample curves.
A simple lightly interfaced waistband made from a narrow strip of fabric approx. 4cm wide and 3 cm longer than your waist circumference plus a seam allowance of 1cm will work well.
If you are inserting a placket opening in the yoke, position it where you want it, we usually place it on the front left quarter. Click here for the link for sewing this simple placket.
Sew the placket first, and add the waistband last job, after the second side seam and hem are finished.