How to sew a Knit Ribbing waistband?? Help

Hi, I making some shorts for my toddler son using Tiedyediva Awesome baby shorts pattern. I want to make the waistband using knit rib for extra comfort. Am unsure how much to reduce size of waistband too in relation to waist measurement of pants, also will be putting in elastic as I dont't think rib will be enough for stretch.
If anyone can give me some tips on this it would be much appreciated!
Oh body of shorts will be woven

Hi there! I agree with you that using the ribbing as a casing for elastic is a good idea. Here's what I would do:

1. Measure your son's waist and cut a piece of elastic that measurement plus 1"

2. Cut the ribbing the same length as the elastic. Make the piece wide enough to be doubled and then sewn to the top of the pants.

3. Sew the ribbing into a loop, but only sew half-way up the ribbing. You want to leave a spot to insert the elastic.

4. With right sides together, pin the ribbing around the top of the pants, and line up the opening with the back center seam. Make sure the opening for the elastic is facing the inside of the pants.

5. Thread the elastic through the ribbing. Overlap the ends 1/2" and sew.

6. Allow the elastic to become enveloped by the ribbing, and hand-sew the opening shut using a whipstitch.

I hope that helped!