I have the equivalent jacket from 2018/19 (?) It's SO good in Whistler rain. It is a very long jacket: since I am short with narrow shoulders + wide hips, I have to unzip the bottom 6"/15cm to create enough room for my hips. I wear an XS tho...since I don't wear a down midlayer, it turned out to fit okay. (Mind you, that was 5lbs ago...) It's not that stretchy tho & I have a hard time cramming in as much as in my softer/more stretchy jacket from Lole (which is what I'm wearing in my profile pic - I started carrying those silicon 500ml waterbottles they sell at the WB shop), so maybe the recommendation for the S will be the right one.
As a perimenopausal woman who runs very hot and hates being sweaty, I usually just wear a base layer (Lole yoga top) and midlayer. The midlayer varies by season/temp:
1) Really cold (significantly below -10C or 0-15F), a down puff
2) Jan in Whistler (daily max -10C to -5C ) - Smartwool midlayer with puffy vest built
3) most of the time at Whistler (-5C to 0C) Patagonia R1
4) spring skiing: thinner-than-R1 from MEC or thin wool jersey zip-up from Smartwool
Note that I wouldn't like to head up the Peak Chair or Glacier on a cloudy day in combo 4 (like I know I'd be totally shafted if the weather changed) & I wore 3) all of the last week of March when it was -2C max each day and a bit of cloud. I was freezing on Jersey Cream + Crystal, but only for a minute when each chair crests over the ridge and suddenly is exposed.
Hope this helps - and look forward to meeting up with you and
@kiki at some point next season!