I have not advocated mixing brands/models of cables, though I'm sure it would be fascinating to try. I would think the results might be unpredictable, good or bad. All iterations of the Schroeder Method I have done with two identical cables have been successful, extremely positive. That seems to be fairly consistent in trails among interested parties so far.
As regards where precisely to place the doubled cables, I have encountered distinctly different reactions, advice and warnings. Some such as Taras of TEO Audio are cautionary, while other designers are dismissive of any real world danger. Two very well know designers who know their stuff, let's say, downplayed the danger of placing Schroeder Method ICs (presuming of identical cables, not mixed) and said there should be no problem.
Who should a person believe? It seems there is much more not known than known with certainty, even among those who know theory thoroughly. So, I'm not about to eliminate the "do at your own risk" disclaimer.
At the same time, David Belles, who I discussed this with in depth while in the Belles Audio ARIA Preamp and Mono Amp review, was quite comfortable with granting permission to try it with his components. I thank him for his contribution to understanding and the go ahead to try between the ARIA preamp and Mono amps! The result? Splendid! Wonderful! Powerful changes along the same lines as when using integrated preamps to amps.
Am I saying it's all good, ok to do this in every pre/amp combo? NO
Am I saying it's free and clear, that the ARIA gear is good to go with Schroeder Method for any conceivable combo of ICs? NO
I'm saying I had one outstanding result so far between pre/amp. The result was good enough that I won't stop there; I'll be testing it some more. I'm not recommending people ignore the advice to discuss with their manufacturer/designer and simply slap together whatever gear with the doubled ICs. I would rather err on the side of caution than foolishness. But, there's no way I'm letting this lie; it's WAY too powerful to ignore.
The one safest connection for Schroeder Method seems to be ahead of preamp. But, I have done many connections now with integrated DACs with preamp function out to amps. So, obviously pre/amp is not blowing up gear, at least not in about 10 instances I have tried.
Most recent is between Benchmark DAC3 DX and AHB2 Amps. (NOTE, this is NOT endorsement by Benchmark!). Oh, my, is this an amazing result with the Schroeder Method! Riveting performance way beyond single ICs.
