[TowerTalk] Fair rite materials for choke baluns

[Rudy Bakalov]

I have been thinking of building a few chokes for my station and long feedline runs. As I started looking into the different material mixes that Fair Rite offers I came across some that have not received any attention by the ham community, at least judging by the lack of written materials. Mixes 31 and 43 seem to get all the attention.
So, I was wondering why no references to mix 52 for the higher ham bands and mix 71 for 160m? Looking at the Fair Rite online catalog it seems that a 3 toroid design, using cores of materials 71 (160m), 31 (80-40m), and 52 (20-10m).
I also looked at this table, which also seems to indicate that 52 is better than 43
http://karinya.net/g3txq/chokes/

So, what am I missing? Why is 52 rarely mentioned and the debate is usually 31 vs 43? Does it make sense to build a "universal" choke using 2 or 3 different cores to cover the entire 160 to 10 m range?

Rudy N2WQ