Play an HX3 Hammond clone (excellent!), an SK2, and NUMA Studio Logic Concert piano. Went to the US to buy the SpaceStation since we didn't have access to them in Canada. I don't use it with the HX3 because there are 4 outputs and 32 output options and there are only L & R inputs on the SSv3 and so the amount of time it would take to find an optimal combination as well as the lack of the power bottom end is prohibitive for me. It is running through a Fender SuperBassman 135 into an extended range JBL pro Fitzmaurice Jack Lite cabinet - awesome! And the box with speaker ways only 45#s!
Now to the SSv3 - it is really good with the Numa, especially with electric piano patches. It really shines with any patch with sauce of some sort on it. The way the SS works is by comparing the left and right signals and then feeding what is different to a separate amp and horizontal speaker system. If there isn't much different L to R then the stereo image is proportionately weaker. When you set it up, you have to be sure not to be sitting beside the side vent speakers, because all that comes out is the differential signal. Nor do you want to sit in front of it as you can't hear a balance of side to front. I use an amp stand and lay the SS on its side and bounce the side vent sound off the floor and ceiling and keep it about 10 feet away - VERY HAPPY.
I thought about the dual PA powered speaker system, but with that you only get stereo at one point in the room and it degrades to just left or right channel the farther you move away from that sweet spot. With the SS you get 300 degree stereo and it is the same everywhere. Using a 2 bin system is an ideological illusion because you don't even get stereo on the stage - only at the convergence point someplace in the middle of the room. This is why live sound is always mono.
The Numa has the best acoustic bass patch I have heard and I want that woody clarity when I play, so I am wrestling with whether or not to add the Behringer Euro 1200. But Organ pedal bass is less clear and I think I may go there. Currently the SK2 is in the hospital so I haven't tried it with the SS. The acoustic bass patch is killer with just the SS3
Also don't know why you want to use a Vent. I think too many guys spend way too much time trying to perfect the hardware instead of working on their playing. I can tell you with the HX3 that I A & B'd the Hammond / Leslie combo side by side with the HX3 JackLite system with synthesized Leslie and I could not tell the difference. And I've been playing Hammond / Leslie combos for about 40 years so think I should have some cred on that. The synth Leslie on the SK2 is maybe a bit weaker than the HX3, but really? If you're recording a career defining album maybe it is relevant. For the average gig - why would you haul a 150# Leslie around?
So if the SS isn't sounding good, you need to do the work and resolve the EQ and the orientation. The thumbs up are right! If all else fails - phone Aspen - he is always happy to talk to you.
Know this is a reply to an old post, but hopefully it will help someone else...