As I said before, there is very little support/evidence for donor matching. There is strong support/evidence for donor quality.
Of course if you have a complex puzzle and certain people have certain parts of it, then matching them with the people who need those parts will be useful. But if you have people who have the whole puzzle, or the vast majority of it, then you can use them for everyone.
There is barely no evidence for anything as most clinical trials are bullshit, they use all the same subjects as if we were all the same, without keeping in mind that patients have:
-DNA differences
-Current microbiome distribution
-Probably some other DNA expressions even sharing the same genes
-Different blood work
So subjects with all these differences are used as baseline when they all are so different, and they even bother to consider as "science" the outcomes of their studies when the subjects are so different and all those differences are not kept in mint?
Then they see that for conditions like U.Colitis where there is extensive research, the see one donor works for 7 patients but not for 2, however another donor works for other patients where the previous donor doesn't work?
Why don't they focus on the differences between the patients that can recover and those who don't to find the underlying cause (at boths sides) that make donors and procedures successful?
As an example (summing up very much), it might be that certain donor X with a high distribution of A bacteria in his microbiome, works wonders for patients with a high number of Clostridia but not for those with a high number of Bacteroidetes that seem to be those patients that not respond.
Then you can add DNA to the equation, adding typical genes like IDO2, MTHFR making it more complex but also easier to predict and match even before the procedure.
Also some donors might be very high in lactic acid consuming bacteria, that can be very helpful for people with CFS, but not for people with MS or depression (again, just a silly example of the idea) who are depleted of those bacteria genuses. So this donor will not help with this patient condition but will help with that.
That's where I want to focus and I think should be all the efforts put on, not only on the quality (that of course is the number 1 factor) but on the compatibility and suitability for each condition.