Transfiguration Temper Supreme cartridge loading

I'm trying to optimize the cartridge loading for my Transfiguration Temper Supreme (which has a 7 ohm impedance) with my Spectral DMC-20 preamp with internal phono stage. There seem to be benefits/trade-offs for the three best settings I have found: 10 ohms, 30 ohms, and 100 ohms.
10 ohms seems to give the most detailed, airy presentation, but with about half the gain, requiring me to turn up the volume control half-way just for reasonable sound.
30 ohms loses a little bit of the realism, but is still pretty open and detailed.
100 ohms loses more of the airiness and detail, but seems to have a better soundstage.
I'm tending to go with the 30 ohms, but I might prefer the 10 ohms if I didn't have to go so high with the preamp volume control. I've seen all kinds of recommendations (including from this forum) regarding the optimal setting. I am getting confused and need some guidance.
Trust your ears.

It really doesn't matter what anybody else thinks.
There should be no problem going up on the volume control as long as you do not have noise issues and you have ample dynamics. If so, then I suggest going with 10 ohms.
Thanks. I'm going back and forth between 10 and 30 ohms to hear the difference in just those two now. BTW, what about cable impedance? Do I just measure it with an ohmmeter and it adds in series with the cartridge impedance? I'm thinking I will need at least 30 ohms when you take a cable into account, though it may be even more. If I remember correctly, the cables connected to my cartridge via a Wheaton Triplanar tonearm are Cardas phono cables.
Cable impedance is trivial as far as loading the cartridge. It's likely to be way less than one ohm. However, the fact that you have a significant loss of gain when you use a 10-ohm load (not surprisingly), indicates that the cartridge is over-damped electrically. But your statement that you prefer the sonics with a 10-ohm load vs other loads up to 100 ohms over-rides all the technical stuff, IMO. I would still urge you to try higher impedance loads, e.g., 1000 ohms. You might be pleasantly surprised, and you would get back all that gain you are losing. The sound ought to be a lot more dynamic, too.
I'll try 1000 ohms, along with a few others, over the next few days, but I've now switched back to 10 ohms and am loving it. I hear more details, many of which I've never heard before, and the 'electronic sound' has largely disappeared. Now, would the dynamics be compromised by the cartridge itself or the electronics trying to amplify the signal? If it's the latter, that may not be a problem, but please correct me if I'm wrong, as both my preamp (Spectral DMC-20) and amp (Spectral DMA-180) are capable of very high currents.
With further listening, I found the 10 ohm setting to continue to sound excellent, but I did find the dynamics to be somewhat compressed. I tried 800 ohms, and the dynamics were much improved, but the air around the instruments and vocals was significantly worse. Also, instruments such as piano and saxophone became much less 'real' sounding and took on a more metallic/electronic sound. Surprisingly, the noise floor also seemed to become increased. Maybe for this reason, or maybe something to do with the increased dynamics, the instruments became less located in space...everything kind of ran together.
So, I switched back to 100 and then 30 ohms, and I found the latter to give the best compromise between the clarity and correct space of the 10 ohm setting and the dynamics of the 800 ohm setting. And, it's not so much of a gets both clarity and dynamics close to just right for my ears (and I think it's pretty accurate as well).
My guess is the right setting is between 10 and 30 ohms- Lewm is right about 10 ohms being overdamped. If the load reduces the output of the cartridge, then it is too low.