I have a 26 year old, rusted to hell, dog ugly, and likely dangerous Federal
Pacific AC disconnect with a non-fused 60A breaker.

What I would like to do is replace this disconnect panel with 100 amp 6
space exterior panel with a 60A breaker for the AC, and use one of the other
spaces for a 20A GFI protected 110 circuit.

Anyone see a problem with my idea?