Yeh.... my fault - I misunderstood - and got confused between power stage and power station... happens lol.
I did think it off that you were using the Suhr reactive load when the power station is also one of those lol.
HOWEVER, the Suhr reactive load would have put the signal down to line level (im guessing but fairly sure). The question is - what signal level does the Pstage need? Ive been finding it hard to come up with that answer as SD dont make it clear.... They say it can be used from a pedal pre-amp - which isnt line level its guitar level which is different.
I asked them about the AFX outputs - as there are -10 and +4 versions on trhe main outs but the other outs are null gain (ie instrument level really). There answer "dont feed it +4 youll clip the inputs" They didnt clarify further ir-10 was OK or if it needed lower ideally. Realistically wed need to know the ideal input signal (+4/-10,line,instrument) for best dynamic range - or its all guesswork.
Now regards LX11 v Power stage 700.... cant help there. I CAN help in a similar situation as I have the SD Power Stage 170 and the Fryette Power Station 50 (original). That should be a similar level of comparison.
From the AFX - I prefer the Seymour Duncan. This is because the AFX replicates speaker resonance/.interaction between power amp and speaker BUT the Fryette being valve (so has an output transformer) does this naturally. What you end up with is emphasised thump and top end. it sounds and feels great - but its not right. The seymore is much more natural in that regard - though it does seem to feel a little compressed - just a little though.
With a valve power amp driving them however - the SD does feel a little less dynamic and compressed while the Fryette is more alive, and open.
Upshot - with modellers Id use the Power stage (particularly with the AFX but also kemper - not so sure on the others), with real amps (as an attenuator, or a volume booster depending on the amp size)the fryette.
Ahh makes sense. Yeah so many abbreviations can get things convoluted. Not so surprisingly I have seen a handful of threads that got sideways because of the Powerstage and Power Station. Heck I a pretty sure I referred to them wrong even though I am not 100% sure haha.
So back on task now and on the same page.
I originally got the Duncan for the reasons you mentioned, for seamless continuity between my presents across all monitoring options ranging from studio headphones, FRFR monitors, and a few real cabs. Wanted to keep the same presets in my Axe Fx III for all of this.
Then I started getting back into tube amps. I got down a rabbit hole that started with my obsession with the Mesa Mark IV then the IIc+ which evolved into the Wizard amps (currently own a MCII KT75, MTL MK II 100w e34l, and MCI 100w ee4l). The Wizards are end game for me which is unfortunate given that they don't exist in Fractal land. Good and bad news is the new Neural Quad Cortex does an amazing job at capturing/profiling amps, much better than the Kemper, and netting something closer to what I am chasing than what I was able to squeeze out of the Axe Fx III. With all of that said, the Axe and my tube rig have both spoiled me with the luxury of a wet/dry/dry/wet stereo rig (note, in a mid way point in life where gigging is out of equation with 3 young kids, so getting my rocks off as best I can solo is all I have for better or worse). Anyway, the QC has its failings for the time being with one of them being not enough processing power to pull off the signal chains that I want that would allow me to be able to leverage the Wizard power amps to my stereo cab rig (i.e. just running the preamp capture tones out to the FX loop returns on the amps) and also using the power amp captures and modulation for the FRFR outputs.
Therefore, the option that I was hoping would get me by in the interim was would be to use the SD PS 700 that I already had. But after trying it out, I realized it had a sub par results compared to what I have become spoiled with from the Wizard amps. At least, with how I was using it.
You bring up some interesting comments about the optimal signal level to feed the Duncan power amps. Like you, I understand the Suhr reactive loads to output line level signals which has worked well when I setup my my Axe III and QC returns for this signal level. Also, I have a Boss Waza Tube Amp Expander that I would set to a line level output and get equal volume level when switching back and forth between the TAS and the Suhr with the output know around 75%.
Also, I tend to agree with your pro/con assessment on which power amp option would probably work better for each application. The tone and dynamics that I was getting with the SD PS 700 out of my cab was very very close to what I was getting out of my stereo Atomic CLRs and even studio headphones (Audeze LCD XC) with a matching IR, so the seamless continuity that I originally bought it for was absolutely there. TBD for my own personal on how much better the Fryette PS or LX II power amps might actually be on the feel and dynamics might be for my application. Seems like it is almost certainly expected to be an improvement, but unsure if it is a meaningful enough improvement to be a worthwhile upgrade.
Sorry for the wall of text, but the convo kind of carried on this way.