Thanks for the advice everyone!
I did a little more research and found how to calculate the ideal VAC out of the amp. The ideal power range listed on the SI website (cached) for the MKIV is 200-350 W for a .5 ft^3 enclosure.
So if I want to be really careful I can look for sqrt(350 x 2) = ~26 VAC out of the 1100.1 before I connect the sub.
Also I found a great post by Andy on the Audiofrog Facebook page about setting gains in an active system. Had to reread it 20 times to make sure I understood everything, but it made me much more confident to push it to the limit.... (limiiiiiiittttt!)
Sources:
Sonic Electronix Youtube
Audiofrog FB - Setting Gains with a DSP
Edit: aaaannndd I just noticed my posts per page count is way too low. Didn't even see the last two posts.
Also I realized I put DSP.3 instead of DSP.2 that I have. Phew. These silly mistakes are why I worry about blowing shit up haha...