Do you have 2 channels open on the amp?
Lots of ways to do it wiring wise, tuning will be the issue. With no DSP, might have to use the same spec speaker.
And to add to your comment about the DSP, it is very involved if you know nothing about it like I did when I started. You might be able to find someone up there to tune it for you.
On another thread here I just posted a link to a video from Da Funk Shop. Those bikes are tuned perfectly and that makes a huge difference.
2009 Road Glide. 16 in Vindikta Wild Cats. Aquatic AV, Stinger 700X4 to MMatts, Audiopipe horns.
6900pros in the lids w/ sspn.4 1000d, tuned with DD Audio DSI-2. S&S 106, lifters, push rods and AC. Drago 2. CycleRama 575. Progressive monotones -1in. 12in. HD adjustable rear shocks. Painted inner fairing. Tuned with TTS. Blacked out!