The sealed vs ported thing is myth.
If your goal is to supplement movies in any way, I would urge consideration of the Monolith 12". I think that will be far and away the strongest solution for your scenario, even if you are say 95% music.
The SVS 1000 series are good, but limited. Rumor has it they will be releasing an update to the 1000 series very soon, too.
The RSL Speedwoofer is by all accounts a good Sub, but it will not be at its best supporting any HT as it rolls off in the low 30Hz area. They say it does 20 Hz, but to what extent, I can't say.
Based on the description of your room, I would say you could easily be looking at an open room volume of 3500-4000cu.ft. That is not a small room.
The Subwoofer will act on the whole open-room volume, unlike your speakers which are much more influenced by your distance-from. I'm not arguing that you need to pressurize the whole space, but you should be mindful that the whole space will have an impact on you and your listening area.
While things are out of stock, I would recommend being patient. Buy the best Sub you can, even if it means waiting a month or two longer. Good quality, clean and linear bass will be the reward!
It will be worth it.
