I use the exact setup you described. Sold my Black Diamond 188 touring skis with Kingpin and my Dynafit boots for some 192 Whitewalkers with Pivots /Cast and Full Tilt Ascendants.
The Whitewalkers are fairly light for their size and dimensions but the whole setup is definitely heavier than my old touring setup but way more downhill oriented, which is what i was looking for.
Switching the toes with the CAST system is easy and i can recommend the whole setup.
I have not put it to heavy use yet because of the lack of snow in the last season and this season but i always had a blast when using the setup.
You can switch to the Pivot Toe and use them as a very solid Pow Ski which is also a nice option.