well, there are many controller choices ranging from the very expensive to "OMG, I could buy a car for that kind of money" and everything in between. What to get depends on what you think you want to spend as well as what you want to do wiht the controller.
Software controllers can be quite powerful for the money, especially compared to what you'd have to pay to get a dedicated hardware lighting desk with similar capabilities. At the low end, there is MyDMX, which definately isn't a "low end" kind of product.
As far as low cost controllers, the Elation DMX Operator is about as low as you'd want to go. It's heavily scene based and limted to 192 DMX channels, but you can still do a lot with that. Not an ideal option if you want animated control over lights like scanners and movers, but can be used with them no problem.
Basically, if you're going with lights that do movement or you want to do cool things with color washes, software is the way to go at this level of the game. MyDMX is easy to use and affordable with loads of features. Play with what you've got a while, because you're not quite at DMX level yet. You've got your signal flow down, now you just need to do some basic DMX self-education. During this time, you can research controllers and software solutions to best use your money.
I definately agree with you in regards to this manual, it's lacking in many key areas. I could probably figure this fixture out myself if I had at least 1, but would need at least 2 to do master/slave. But really, I'm more concerned about DMX functionality since when and if I get 4 of these(leaning towards WILL), I intend to use them in DMX mode only, and control them using MyDMX
Nothing against Master/slave mode, it's there for a reason. But this manual just confuses me. Not having the fixture in front of me to mess around with, I find myself just unable to remotely relate to your fixture.
Do this, download the manual for the Mega Panel and see if that may offer any insight. While they aren't exactly the same, they no doubt probably have many similarities. It can't hurt to try.
The only other suggestion I can offer is to throw them all onto the same DMX channel in the same DMX channel mode, then select your first in line(the one with the open DMX IN port) and throw that into Master mode. Then wait and see.