There aren’t really any seatposts that are bad for carbon railed seatposts any more. Even the posts which look like they put the rails in undesirable 4 point bending have nicely smoothed edges and wider contact points to reduce pressure compared to models from a while back. I wouldn’t be fooled in thinking you need something special just because you have carbon rails.
Main thing to avoid is a post with a sharp edge in contact with the rails but these don’t really exist any more. I am very happy with this 135g £60 seatpost with my Tune Speedneedle.
I have had a Thomson Masterpiece in the past but dented it quite quickly and it is both heavier and more expensive than the example in the link. Up to you, but personally I wouldn’t be paranoid about a “safe for carbon rails” section in the description. Just torque the post up correctly and you are good to go.