Change dimension of different objects in group to specific value

Question

I have several circles of different Width and Height in a group. How can I make them all 0.3mm W and H?

I've found this answer, which uses Object > Transform > Transform Each... But that only allows to rescale each element in the group by a certain percentage,not absolute value.

Answer 1

1. Ungroup everything
2. With all objects selected, go Effects > Convert to > Ellipses
3. Check Absolute and enter W & H values
4. Click OK
5. Option: Group back
6. Option 2: Object > Expand aspect