Take a look at the Franchi SLX and check reviews. ~6.3 lbs vs. ~7.8 lbs for the CXS 12 ga.
Instinct SLX | Franchi Shotguns and Rifles
I think your sans dog chances are better out west than here where the cover is usually ridiculously thick. Assuming you learn some spots that hold grouse, cover out there is likely to be more spotty, with some open land between good areas of cover. If you or better yet you and a hunting partner can spread out and hunt some cover, work it so you come in where it's wide and work your way to where it narrows or comes to a point. If you don't flush anything along the way and the birds like to run, they'll usually flush once they realize they have run out of cover. If there is another area of cover nearby, if they are older, smarter birds they'll usually head for that so you can somewhat predict where you'll be shooting. I had success doing this in central CA for valley quail.
@peterk123 - just making sure you catch my added info