Nice eggs.
I am getting about the same, my eggs are medium - large,
and some terracotta and others about a 6-7 on the marans chart.
Their egg color is a definite work in progress, but I want my chickens to live as freely as chickens do as possible. I don't want to burn them out.
I want my hens to be consistent in their egg color, Like my Marans, Free ranging helps egg color, but in doing so they are vulnerable predators. I know through experiencing it 1st hand, I lost a group of 10 roosters in a 4 day period.
I Found in my studies that diet affects their egg color dramatically,
When I put them on a specific & controlled diet their eggs are dark as can be! If I don't then eggs range in color especially when penned up.
Stress also affect egg color, & Penedesenca's do stress easily, as most of you know penedesencas are know for their wild sides.