We have several inexpensive soldering irons. But when I built my K2:
They recommended a temperature-controlled soldering station. Kind of expensive.
Soldering has always been my bane, but I've discovered that keeping the joint (and iron) clean is an absolute requrement for making a good joint...and the correct temperature is a close second.
That said, for projects of the complexity you're contemplating, simpler is probably better. A Weller station like mine isn't cheap.
Good information here.