Ugh... get a drink.... TLDR: Buy the Stratus set in YOUR size, no need to up-size. Get one or two top/bottom layering pieces, from anywhere that fits the 'job' for that layer.
I have too many Sitka pieces. But, I have something for everything x4 when you mix and match. I really like my Stratus set and highly recommend it to anyone who asks. I am 6'2 195 ish, athletic build, south central PA but hunt around the state at times. I bought the jacket in an XL before I realized the cut of the L was actually what I needed. I would trade down a size if I came across the right guy to take my XL.
For bibs, love them. I have a L and they fit perfectly with multiple layers. Overall, I hate layers, which is one reason I went all in on Sitka. I try to get by with only three layers, including base. I am usually wearing an Under Armour tech compression top (don't count this layer), short or long sleeve pending temps.... As I get older I tend to run colder... but I prefer/love hunting in the frigid temps, go figure!
I tree stand hunt almost exclusively and my longest walk is maybe 500 yards from the house, shortest 100 and dressed 'heavy', I need to unzip until settled in. I hunt well over 400 hours a year, Oct thru mid-January for deer and chase squirrels though the end of February in this same gear.
Gloves: I use the early season glove pretty much regardless of temps. If it's freezing, then I'm in my Fanatic jacket and that hand warmer is beyond description

Always take some mid-weight glove in my pack but seldom use them.
How I layer/temps:
Warm 70+
+ UA short-sleeve
+ Sitka lightweight hoodie
+ a lightweight pant, usually Equinox (2020) but they can be really warm sometimes; trying a pair of Kuhl pants a friend gave me for this year.
Mild 60-70
+ UA short-sleeve
+ Sitka Fanatic Light jacket (long ago discontinued but sub a Stratus here)
or... Sitka Fanatic hoodie if it's not breezy/late evening hunt where it might get chilly
+ light weight pant, add a lightweight base bottom if toward 60 and breezy
Cool 50-60
+ UA short-sleeve
+ Fanatic hoodie
+ Lightweight Fanatic jacket or Stratus
+ Lightweight base bottom
+ Equinox pant
Chilly 40-50
+ UA long-sleeve
+ Fanatic hoodie
+ Stratus jacket
+ Heavyweight Merino base bottom
+ Equinox pant or lower temp, then Timberline pant (love them if chilly air)
Cold 30-40
+UA long-sleeve
+ Heavy Merino base top
+ Fanatic hoodie
+Stratus jacket
+ Heavyweight Merino base bottom
+ maybe Equinox midi pant toward 30 degrees, they fit under the Large Timberlines just fine
+ Timberline pant, Stratus bibs if any wind instead of Timberlines
Cold-Cold 0-30
+UA long-sleeve
+ Heavy Merino base top
+ Cold Weather Hoodie (discontinued, now "Traverse" line)
+Fanatic heavy jacket
+ Heavyweight Merino base bottom
+Equinox midi pants (do not under-estimate their value)
+ Stratus bibs
+ Incinerator hat