All the evidence I have seen (dress regs, period photos) show the blue wedge being worn with the khaki summer uniform (in Canada) and also with khaki shirt and shorts in far flung places like Burma. The old saying that, "the further you get away from base, the less formal the dress regs" seems to be true (again, especially in Burma) but even then I have never seen a wedge of any colour other than blue. I have even seen the blue shirt being worn with khaki shorts and blue wedge in Burma (along with Aussie style bush hat).
This is just my observation and is not meant to be taken as anything other than that
As for the eagle/goose/albatross...I'll let someone else point that out (as it will start a heated discussion