I don't know about an exact temperature, but when I solder big wires with Deans connectors I use my 40W soldering station and turn the knob to at least 3/4 of full. When you are using that hot of an iron, though, you have to remember to not leave it on the connector longer than you need to, or else the plug will start to melt pretty quickly. Also, don't know if you're already doing this, but make sure you tin the connectors with a good amount of solder (so there's a slight mound of it) and tin the wire all the way through the part you stripped (it might take several inches of solder to do so). Good luck!