the bigger question is has your frame been faced? Not matter what tool you use to fit the headset (and I favour the wood and threaded rod press myself) if your headtube is out whack then your press, diy or not, is not going to get the cups square to each other.
The same with your BB shell, which is more important with EBB cups and less so with a trad square taper BB.
There are few bike co-ops near me in London who have these type of tools and you can "rent" a bench and get some advice at the same time.
Edit: The star nut doesn't need a tool either, it's a fairly crude device and provided it's put in square to the eye then is good enough IME.
If your crown race is split it's even easier than a non split crown race should go fairly easily.
good luck