Initials logo idea

Hi everyone,

I'm playing with my new personal logo and I would like to use my initials of PH and transform them into the cube which I'm almost there I think (Cube like a basic 3d object - I want to focus on 3d design :) ). But there is still something what I don't see what's wrong. I would like to have same width on the top and bottom and between P and H. Technically the P is same like H but optically the H looks wider. Also I tried some grid....

I'll be happy if you can suggest any opinions and ideas what to fix.

Thank you very much.