So interesting given that i experience most leather sourced from Tärnsjö to be pretty thick when coming from Skoaktiebolaget. Given that i have found it excellent for more sturdy modells and never actually considered it suitable for a shaft. On the Skoaktiebolaget thread i think more was of this opinion and it was even noted that given the thickness Tärnsjö grain rolls a bit like cordovan when breaking in.
Location of the tannery in question btw, https://goo.gl/maps/RMpAEvhuaav. Note though that the county side of Sweden are not that well covered by Street View and similar.
I have both. The vass one feels thinner.