hmm well from little I have seen it only bears a very vague relationship to the reality. The Bad Queen lady is nothing like Margaret in any shape or form, the fat king who karks it in ep 1 is a lot like Edward iv but his son is the polar oppostite of Henry vi, so it's a mistake to get hung up on how close the connections are. The only valid Richard iii I have seen is the dwarf, and he is a likeable wee fellow with a disability, which ties in well with the modern tendency to see richard as misunderstood.
My reason for Deneris as the Henry vii candidate are;
-from deposed royal family.
-Odd-looking, not-quite human family - ie welsh
It's all a bit foolish to speculate anyway as the odds are the author will drop dead before we ever reach 'Bosworth' anyway.