Currently tekvest, cant remember the name but its the one they designed for back country. Bit longer and not much protection in back since I always have a backpack. Id recommend getting something, thankfully I have never took something to the chest hard enough that a protector saved me but I def have taken smaller hits that woulda had me sore.
One thing I learned about working outside is if your core is warm hands feet and limbs are fine. If you sweat you have issues and get cold and hard to come back from that. Moisture management is key. If I started off being toasty when getting sleds fueled, oiled, packed before even hit the trail Id be sweating my balls off once we actually started being active and my feet and everything else would end up being colder. Maybe if I had a super long higher speed trail in and out I would wear my midlayer coat for that but our trails in and out generally aren’t like that.