Aka Kawa Hime is just a dwarf sport of Sango Kaku found by Del Louck of Del's Japanese Maples in Oregon so it should share most - if not all - of SK's attributes as well as drawbacks. The red of a coral bark maple is most intense in winter but I can't tell you why one would look more red at this time of year than another........one raised under cover as opposed to being field grown? It's a possibility.

All JM's that feature red or coral bark tend to be extremely prone to bacterial blight, Psuedomonas syringae. I haven't done the research into why this is so but there must be some genetic trait that is both responsible for the red bark as well as making the trees vulnerable to this issue. They can ALL get it - SK, Beni Kawa, Fjellheim, Winter Flame, Japanese Sunrise and Aka Kawa Hime.

I don't know if this answers your questions, but I would select the tree based on its form rather than its current branch/stem color. If you want a smaller tree than SK, then you could look at the other dwarf coral barks - Fjellheim and Beni Kawa.

Oops, I meant to say Beni kawa is the tree I saw compared to Sango kaku in original post. But from gardengals helpful reply it may not matter.