Hi Ikea,well it's always said Sango Kaku needs both sun and cold to colour up.This last summer mine lost all it's redness though usually very bright.The early part of winter was our coldest for many years but it still didn't colour.However since the very cold snap we've seen more sun and now the redness is returning.So from my experience,the sun plays more than a part in the colouring of the bark.As long as it can handle the heat it should be fine,here in England mine is in full sun....oh maybe misunderstood you,I think any lack of uniformity will only be noticed on largest stems and trunk,but these will have lost that dazzling red anyway.