Iroko will weather better than (European) Oak and go a silver grey.
Iroko can also be oiled for a spectacular appearance. Iroko dust is
carcinogenic and the oil can be a bit nasty too. Oak dislikes iron,
Iroko dislikes brass.

You can use individual short panels with Iroko, as a horizontal
cladding, very attractive. No need to overlap and it gives a very
attractive architectural finish.

Why not use a coloured render, textured render etc?