I have not hiked the PCT but I have backpacked in the Sierra some. According to this...
either will work although it looks like they have both had a refresh for this season and haven't had as much real world testing.
The CS generally it looks to be an improvement over the previous version. Mice can apparently be a problem in Washington and having the higher solid walls on the body is an advantage over lower mesh. The MSR HH already has that design.
Of those two I'd opt for a lighter tent but I'd probably go with my BA Tiger Wall with modified guy lines because it is lighter although the mesh comes lower. You will definitely want to use some kind of footprint with the BA tents where you might get away without on the MSR.
The reviews indicate that the MSR may need seam sealing which is somewhat surprising!
Unless you need it this year for other reasons I would probably wait and buy a tent later...maybe once you get here to save on shipping and import duty if that is a thing for you.