"From what I have read, it would be best if I wire the voice coils in series for 8 ohms and use the 3000 DSP in bridged mode like this"
there are two ways to wire it and they produce the same result.
1. wire coils in series for 8 ohms per driver. wire drivers in parallel for 4 ohms net. connect to amp and run amp in bridged mode.
2. wire coils in parallel for 2 ohms per driver. wire one driver onto each channel. connect to amp and run amp in stereo mode.
method 2 presents the least confusion with connecting the speakons, I think.
either way, same result.
"are there any other steps I should take while I still have the box open?"
be sure to check your wiring with a 9v battery. you want forward cone motion with + on sub to + on battery. if you get no motion, that means the coil wiring is screwed up. if the cone goes in, it is wired backwards.