For my 8350 core 0 is usually the main core but say about 30% of the time it can be another, again usually an odd core being windows treats the even cores as HT.
I am not sure i am understanding what you are trying to say. but i i do i can not confirm you findinds in all of my time measuring (logical) cores and palying with affinity.
You don't have a main core and then a HT core. You have two logical cores leading to a physical core. it doesn matter which of these two paths your thread takes it still ends up on the same physsical core.
The only issue is the load that physical cores get from the other logical core assigned to it.
The belief that there is somehow a real core and a HT core in the list of logical cores you are seeing in taskmanager is just plain out wrong.
If I misunderstood what you where trying to say I apologize.
-- edit --
i wrote HT core here replaced it with CMT extra cores or whatever proper name would be for it in AMD's last Gen CPU