Volleyguy
The MR Clarity cap is not a mass produced cap like their others it is a brand new line, and from the Humble hifi site with the tests the one just below the new clarity MR is the DTAC which was tested and pretty much ranked the same as the mundorf.. The Clarity cap MR is more expensive, not quite as expensive as the Silver gold oil..
My concerns with Mundorf oil caps is mostly in long term electronic environments of heat, and nobody has really been able to see if newer oil caps will hold up over a very long term or not deteriorate at all.. Speakers I would not be as concerned about leakage or floating from the value as much.
Hence my choice in going this route, the Oil Gold got a 11.5 rating nearly as high as the duelund in the speaker tests..
However the DTAC from clarity cap which is said to not sound like any other clarity cap got a 10.5 and these MR's should be just that much better...
I can tell you this, the MR is quite a bit different approach for sure, I bet they will for about half to 1/3rd the price in electronic applications be equal or better than the duelunds. I used the SILVER oil Mundorfs in the electronics, Great hi's and mids, but bass was not as authoritative being in a Full range application like an electronic device putting out 5 hz to 50 khz for example..
Your Testing is very limited to simply a VERY limited frequency range in your speaker just feeding one DRIVER response at a time... That does not mean they are not great or superior in that single application as you have found they are that good, but for reliability, and for FULL signal unrestricted audio frequency handling, I believe this MR from clarity cap, and such types as VH caps, sonicap platinums, might just be slightly a cut above most of the mundorf and even possibly duelunds in this application for a few un-obvious to the passer by reasons.
I am planning to try your Duelunds in the copper foil VSF config on my own Klipsch horns.. I have full out Alpha core inductor and Jantzen superior caps in them now, The bass would benefit probably ZERO from using a duelund so leaving that alone I will change out my horn cap with the Duelund because I can believe they have that one more step of dimension and smoother noise floor, however I kind of refuse to use the Duelunds that you need to order special in 400 volt at double the price for an electronic application.. I am sure they would be fine, maybe a little magical, however due to the odd Shape, and the "Iffy" results in a full range electronic application, including the fact you will still have more caps changing the sound down the road in the speakers.. I will just believe the MR's will do a better job.
By the way the Jantzen superior caps for about 25% of the cost of mundorfs I believe a better value and sound overall, and are slightly smaller for installation.. you can see the praise on those as well at the humble hifi site, I just decided you can't put all your eggs in one basket of tone.. You are not the first to break ground on the duelunds sounding excellent in hi frequency transducer applications. So I believe you that they are special and worth a shot even at the obscene prices, which by the way I need to use duelund because they are the only ones that will custom make any value you need, any other cap I can't really get it.