I have to say Jens that you are certainly doing great stuff for someone with a hearing disability, I would never have guess that from all the great engine work I've seen from you in other threads in this forum.

As for the engine runs in this thread they all do sound a bit labored down, or missing, to me with the occasional knock. But I also know from making my own movies that the engines do sound better in real life compared to what they do in movies. In my own movies the engines sound a bit over-compressed even though I did the tuning in the first place. Perhaps you could make a movie for the same engine with traditional ether fuel (and IPN) and then one could more easily compare the performance of the non-ether fuels.

I don't mix my own fuel anymore since I've found a local source that will mix small batches to specification with both ether and IPN. To me both ether and IPN or DII are important in order to get that smooth, non-missing, running on moderate compression settings that one is after. While engines can certainly run on other fuels, they do favor the older hit and miss running style.