This tree includes all known SNPs in I-M26. The format is based on this tree which shows mainly Z SNPs discovered by volunteers looking at 1000 Genomes data:
There are probably millions of men belonging to I-M26, they live in Spain, Portugal, France (up to 5% of men in some parts of these countries); and in descendants of Spanish, Portuguese and Frenchmen in the Americas etc, and they also comprise about 40% of the men on the island of Sardinia. I-M26 is found in less than 1% of men in Ireland, Great Britain, the low countries, western Germany, Switzerland, the Italian peninsula etc. but it is very characteristic of western Europe and has a long presence there (i.e. 5,000 year old I-M26 skeletons have been found in southern France and near Paris).
There are at least 11 different SNP-defined groups on my tree, but I estimate that over 90% of I-M26 men belong to the green, blue, or red groups. With 67 STR markers, almost everyone can be placed in one of the minor groups, the green group, the blue group, or one of the red groups. But we don't yet have enough results to know if there are STR patterns that can distinguish between the three red groups.
Probably the PF4189+ group will have many more members besides the "1 English Family". But I don't know which of the three red groups will be biggest when we have done more testing. Unfortunately, some of the important tests are not offered by Family Tree DNA (Z105, Z120, CTS11338, PF4189); these are only available as part of the Geno 2.0 test at this time.
In the near future with more Geno 2.0 results we will learn much more about the three red groups. And we will learn if the PF6947+ group is a major part of the green group or not. But unfortunately Geno 2.0 will probably not teach us much more about about the green group--there is surely a SNP out there that is shared by almost all of the green group, but it hasn't been found at Geno 2.0 or in WTYs so far.