This is for a small to medium size:

To make it bigger add more rows to the cups repeating 6-10 until desired size and chain more than 30 when connecting the cups and making the back piece
To make it smaller, for the cups, remove rows between 6 and 10 until desired size and chain fewer than 30 when connecting the cups and making the back piece.

Use fingering/light weight yarn, one skein was enough.

The Flower of life should not need to be changed in size though the exact stitch numbers where it attaches to the cups may be different.

To start the flower of life, you can make a magic circle instead of slip stitching into the first stitch
You can use i cords or just chains for the straps, I just like the ease of doing foundation stitches