OK, first things first. What tools will I be using?
After talking to a good friend who is an experienced coder, I decided on the following:
Spyder, running Python 3. It seems to have everything I need, including a good debugger, a variable explorer, hot-linking to function definitions, auto-completion typing, Matplotlib, QT, plus a choice of either a Python and iPython console (each with their different strengths). The bundle I went with is Spyder for WinPython-64bit (WinPython-64bit-220.127.116.11Qt5). The QT will be useful later.