If I was in your place (signal tank/electronically controlled) I'd get an adhesive heater designed for heating batteries or oil pans in cold weather and wrap that around the fuel filter housing. Those come in 120v modals so you can plug it in when you plug in your block heater. I know it seems like cheating, but just put a little K-1 in the tank with the SVO and it will thin it right down.

__________________
1975 Mercedes 240d (Daily driver, town)
1980 Toyota HJ45 (diesel) (Daily Driver, Farm Implement)