I have gotten much better at cold starting the Deutz in my 1460. I still have not wired in the glow plugs, but I have started it in the single digits, probably about 8 degrees. I put the throttle up about 1/2 way, and just keep cranking it. Takes about 30-60 seconds, and smokes like you wouldn't believe, but takes off. The starter on the Deutz has no trouble driving the cold pumps.
I think that below zero I would need the glow plugs though.