Boy... questions questions! I'll do my best answering. It's tough to convey things in this world of ours. And so much is subjective. So, this is all from one man's head.........
If you were doing this over again, what changes would you make? I am toying with the idea of going with a Rhythmik bass solution to go with either the Super Alnico's or SUper 3's. My living room is about 16' x 20', with a listening position about 8' from the speakers. My other room (which can be set up as a semi-dedicated listening room) is 12' x 12' with a similar listening distance.
Your room is only slightly smaller than mine. I'm sitting 9' from the mains. So we are pretty similar there. I've not had these set up in a smaller room, so can't share experience in that setting or with the Super 3's, for that matter.
Do you feel the alnico's have adequate bass for the smaller room in an optimized setup?
It sounds like you have SAM's already? Did you listen to them in the smaller room? And the judgement about what makes for adequate bass is very subjective. For me, in my larger room, I was impressed with the bass extension of the monitors, but not enough to live with them without the bass extension help. The bass from the monitors alone would likely improve in a smaller room, but I don't know by how much. There have been at least a few comments from Monitor owners in this forum that indicated satisfaction with the bass without subs.
I will add a comment about the quality of the bass.... It's not like you would hear my system and say how powerful the bass is. Well you might if I was playing Amy Winehouse, but not for the majority of music. It is more that you hear more of the music since bass tones are clearer. You can hear, for example, the plucking on an upright bass in detail following what the player is doing without it dominating the rest of the music. I would characterize the added benefits as increased clarity and articulation rather than increased power or volume (though you can get those with this setup). With orchestral music, you get that fuller sound with more emotion with the low end support.
Do you think that the 8" drivers are better or worse than the 12" solution?
If I understand you correctly, I think this is apples and oranges. If you are using the 12", I assume we are talking about a subwoofer with Rythmik's extension down to 14Hz. The single 8" drivers are not subs. Brian has the amp roll off at 30Hz to make them mid-woofers (actually with a toggle to choose either 30 or 50Hz. He does make a sub with 8", but it is dual 8" drivers to handle the demands of the lower frequencies (FM8). You can get the FM8 with the mid-woofer option as well. In this case, it will switch between extension to 50Hz (mid-woofer) or to its lower capabilities (sub). These are finished subs. The single driver mid-woofer with amp he only sells without cabinet.
If I had to choose between Monitors/subs and Monitors/mid-woofers, it would be a tough call. The subs can extend up to mate with the monitors fine. In fact, I've never tried having the crossover feed the monitors and subs - only ran the monitors full range and subs supplementing. So the monitor/sub combo might work better if I did. Based on my experience between monitors full range plus subs vs. monitors and mid-woofers with the crossover, I would choose the latter. But, now that I realized that configuration I haven't tried, I must try it!
I'll post impressions after I get a chance to do that.
If you didn't have your existing subwoofers, would you have chosen 12's?
If you mean for the mid-woofers, no. The box for the 8" driver is perfect for a base under the SAM's making for the feel of just a pair of floor-standing speakers rather than monitors and separate bass modules. With it only needing to go down to 30Hz, the 8" driver is lighter and faster than a 12" would be (caveat of Brian's claims that his servo is the great equalizer between drivers). Aside from Brian's servo technology and driver size, the smaller driver has a paper cone and a foam surround. You can get a paper/foam 12" from Rythmik - the GR Research version - but Brian claims there is little difference in sound due to his servo technology. The difference is the paper driver can extend higher. The 8" driver can extend even higher than the paper 12 though, if you want to cross higher than about 120Hz.
And finally, do you feel the use of stereo subs/woofer modules are worth the extra resources if you run the satellites full range?
For me, definitely. One or the other if not both. But once I do have the woofer, I am not going to run the monitors (or the low power tube amp) full range. As you have likely seen earlier in the threas, I have a line level crossover to make the blending absolutely smooth. It relieves the main amp and the monitors of some of their heaviest work as well. So by adding bass units you get much better bass response while also improving the midrange. Actually, the extension into deeper bass enhances the midrange, too. Even a guitar pluck now has the added support from below.
Now having the luxury of both the mid-woofers and stereo 12" subs, I wouldn't sell the subs. But if I only had the Monitors and mid-woofers, I would be happy and might not spring for separate subs. 30Hz is low. And these go solidly to 30Hz. If we ever move to a condo or something where the room would be smaller, I would likely move without the subs.
Finally, I will say that the attraction of the Rythmik line is for the mid-woofers with the modified plate amps. If you are opting for regular subs, I would talk more to Louis as he makes subs designed to mate with the Monitors. I had my pair of Rythmik F12's before I had even heard of Omega.
Hope this helps - a lot to digest! ........ Peter