So I finally got ready to do some testing and ended up with unexpected results.
Not terribly conclusive as It's the beginning of the season and I'd rather play than test but.
37* out today.
So I set the Gargoyle up with a old Green Valve Spring and the Blue CCI main spring. I started with the Summer valve insert to get a baseline. All I have is paint from last fall so it's pretty inconstant
Started in the mid-high 270's 27 shots above 225 10 shots under 200 before it finally popped.
I switched to the winter insert you sent me. That was the only change.
Starting FPS dropped by about 40 to the low 230's
Holding the bucket changer in my hand for a few seconds resulted in a 15-20 FPS spike.
I switched to the Silver main spring (I don't currently have any red ones) but that only brought it back up about 20 FPS to the high 240's low 250's. Since I couldn't get it up to the same speed I didn't bother doing a shot count and the old paint made it hard to say if consistency improved.
I hit the field the following day and it was a little warmer, low 40's, I was chronoing right where I like in the mid-high 260's. I was playing so no hard numbers but accuracy even with the older paint was pretty spot on (leading me to believe it was pretty consistent) and I was going 3 full tubes easily before changing the 12ie.
Preliminary thoughts are that this is going to work really well for cold weather but will require it's own spring setup as opposed to a direct drop in.