The workflow I recommend when using Rigify:
- Confirm the character's scale and proportion related to their environment and props, then apply character's transformation (otherwise, an accidental scale reset could ruin the rig),
- Carefully adjust the metarig to the character's scale and proportions,
- Generate final rig from the metarig.
Adjusting metarig scale is preferable than fixing final rig. That's because if a character's scale or proportion is changed, and the final rig must be adjusted, the proper procedure is:
- Unhide all bone layers.
VIS- (visualization helper) bones selectable,
- Adjust all bones in the rig to new character proportion,
- If you use Complex Arm/Leg Rig, so that the hand and feet use 2 bones for each segments, carefully readjust both segments, keeping them aligned,
- Reset all constraints affected by the change, especially Stretch To,
- Reset unselectable all
- Re-adjust custom shapes, because length change affects custom shape's size.
So, confirm character scale, and try not to adjust rig scale after generating. That'll save a lot of your time.