I've been doing some thinking about the above. In the west we tend to have the mindset that if you find a good medicinal plant the way forward, the way to "improve" it, is to extract the active ingredient and chuck the rest away. Part of the enjoyment of kava is the ritual of preparing it, making a relaxing setting, taking your time over the event to make it and keep it something special. I think in part this is what the Kavasseur was getting at when he was talking about the tudei/noble thing, rather than medicalising kava and analysing it so we know everything there is to know about it we should maybe get more into the spirit and culture of it. I agree that the culture side of it is important, to remember where it comes from and maybe pay homage to the kava gods once in a while. For me though I want kava to be an enjoyable experience so any way that I can use the analyses, the COA's and the chemotypes to make my kava experience more enjoyable, say by helping to avoid a certain KL that tends to cause me nausea, then I'm going to take that into account as well. I don't think you can separate the different KL's so easily as you ALWAYS take a certain percentage of ALL the KL's together in varying quantities which is precisely what gives kava it's interest. You can try 10 different kavas and get 10 slightly different results.
Some other points in no particular order...
If it really is the M that causes me nausea then logically absolutely any kava will give me nausea if taken in a high enough dose because sooner or later I will be consuming a large enough amount of M to give me the problem.
I'm surprised to look at the COA for Nene from Kava Europe and find that it is low in M. It seems to have a similar chemotype to my fav Pentecost Pride. This is well reported as a heavy kava I believe? I have to admit I am yet to try it but looking at the COA it looks like it could be one for me according to my theory. I'll definitely give it a go. I'm willing to believe that despite it having a similar chemotype to another more heady blend it could have a different effect just because every kava is a mix of different KL's in different amounts and so all kavas have a slightly different effect.
I had a though about instant and root powder. The COA of quick kava powder from Kava Europe gives certain figures for each KL per weight of dry powder. Well, one thing to consider is that in theory ALL of those KL's will be in your drink in the respective percentages because you're just adding water and mixing. Compare that to root powder when even with a good blender method you're lucky to extract 50%. Something to bear in mind. That said the Pentecost Pride is nearly double the total level of KL's anyway so at 50% extraction you should be getting roughly a similar amount of KL's shell to shell. That explains why a 2 tablespoon session of the instant is less powerful than the 3 tablespoon session of the powder even though everyone thinks instants are stronger.
Sorry this is a bit of an essay, just thinking out loud. I hope this helps someone else at some stage sorting out their kava thoughts.