To my mind, Clogwyn Y Person Arete is one of the harder Welsh scrambles. The gully approach to the top of the Parson's Nose is the easy bit. There is a chimney higher up that is probably the crux. I haven't been up for years, but have needed a rope on that section a couple of times (have always done this route with my dad, and each time one of us has felt bolder than the other and soloed the crux then dropped the rope down). I'd say it was a hard grade 2 or easy grade 3.
The main fun is a steep corner on the upper part of the ridge, but even this is much easier than it looks due to massive hand and footholds in all the right places. This bit can be avoided on the right hand side if necessary.
Last weekend I headed for the Rhinogs to give my new tent a proper test run (ie pitching it more than 5m from the car...), and also to finish the Welsh Hewitts. Surprisingly, the weather was fine for the whole walk: