Not particularly line sensitive - WF or DT. Line weight varies depending on which blank your rod is based on. The earlier 6’8” brown blank 7090xxl is a sweet 4-5wt. The later amber colored blank - also sold as the colorful Herter’s RFSC series - is a 6wt in my hands
Would love to try one of the brown blanked ones. Among my three amber colored blanks, one is a crisp 6wt that can cast a 5 and the other two are softer 4wts that could cast a 5 at short distances but would be way overloaded with a 6.
I mostly use a 4wt cortland peach with the lighter rods but any slightly heavy 4wt that I've tried seems to work well.
First time on the water with mine it took a slight adjustment in my casting stroke.. It's been my favorite small water rod ever since.