This was straight off the John Deere Website. I just picked up some #1 today. I have winterized fuel, but we are expecting temps of -32 deg F next week. My fuel supplier says the regular diesel right now is a 20% blend of #1 and a little more wouldn’t hurt. You should treat also with a good product to help even more with gelling and especially to ad lubricity.
Having trouble starting and gelling are almost certainly 2 separate concerns.
To address starting ease in cold temps, additives that increase you cetane value (not a fan personally) or a block heater can be used to improve performance. The block heater outright eliminates starting difficulty with my hot blooded 4720. It apparently has the soul or a Caribbean islander and has measurable contempt for cold temps at start up. With an hour on the block heater (like today, with it being 16deg F out) it starts like a warm summer day. Click, crank, varoooom... I advocate using 0W-40 synthetic too, it brings oil pressure up much faster in cold weather than the 15W-40 standard.
Gelling is a calculated risk for some and predictable for others. You sound like you want to be in the calculated risk group... At least your dealer suggests being in that population.
I use an additive (power service) for extreme cold - like we are expecting this week (lows <-10F this week:hide. Kero or additive, you need to do something if you know you (likely) have straight #2 in the tank an temps are headed down to the low teens or lower. Otherwise, unless you know you are getting the right winter blend from your dealer, problems are to be expected. If you want to use kero, arlen's referenced the source I'd use. There are a ton of threads on additives for avoiding gelling on GTT as well.