I've owned both but not used both at the same time, if that makes sense. I'd venture to say the Peloton 97 is equally as warm as the Kiln.
I ran the Kiln all last season (over a SS Aerowool) as my mid layer until it got really cold, then i went to the Sawtooth. I wasn't unhappy with it by any means but when I got my hands on the Peloton 97, at a third of the weight, it seemed like a no brainer, so I'm with Turkey in that the Kiln isn't warm enough to justify its weight. Also the Peloton series will dry a lot faster than the Kiln, I sweated that Kiln out big time last year and it took forever to dry. This year I'm switching to the 97 as my go to mid layer over an Aerowool SS or later in the season a QZ Aerowool.
However bringing an additional QZ or T seems redundant to me and kind of defeats the purpose of saving weight with the 97 for little warmth advantage, I would pick one or the other.
I also added in the Kutana 3dfx jacket this year figuring that the weight difference over just the Kiln alone is negligible at only 3.6oz heavier (15oz for kiln, 18.6 for 97 plus Kutana) and adds MUCH more room for flexibility. Maybe consider the 200 for that time of year if you run more on the cold side, but for me the 97 is going to be a for sure go to in my pack until the cold really sets in and then im considering getting the 200.